sys/netinet/siftr.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2007-2009
   5  *      Swinburne University of Technology, Melbourne, Australia.
   6  * Copyright (c) 2009-2010, The FreeBSD Foundation
   7  * All rights reserved.
   8  *
   9  * Portions of this software were developed at the Centre for Advanced
  10  * Internet Architectures, Swinburne University of Technology, Melbourne,
  11  * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 /******************************************************
  36  * Statistical Information For TCP Research (SIFTR)
  37  *
  38  * A FreeBSD kernel module that adds very basic intrumentation to the
  39  * TCP stack, allowing internal stats to be recorded to a log file
  40  * for experimental, debugging and performance analysis purposes.
  41  *
  42  * SIFTR was first released in 2007 by James Healy and Lawrence Stewart whilst
  43  * working on the NewTCP research project at Swinburne University of
  44  * Technology's Centre for Advanced Internet Architectures, Melbourne,
  45  * Australia, which was made possible in part by a grant from the Cisco
  46  * University Research Program Fund at Community Foundation Silicon Valley.
  47  * More details are available at:
  48  *   http://caia.swin.edu.au/urp/newtcp/
  49  *
  50  * Work on SIFTR v1.2.x was sponsored by the FreeBSD Foundation as part of
  51  * the "Enhancing the FreeBSD TCP Implementation" project 2008-2009.
  52  * More details are available at:
  53  *   http://www.freebsdfoundation.org/
  54  *   http://caia.swin.edu.au/freebsd/etcp09/
  55  *
  56  * Lawrence Stewart is the current maintainer, and all contact regarding
  57  * SIFTR should be directed to him via email: lastewart@swin.edu.au
  58  *
  59  * Initial release date: June 2007
  60  * Most recent update: September 2010
  61  ******************************************************/
  62
  63 #include <sys/cdefs.h>
  64 __FBSDID("$FreeBSD$");
  65
  66 #include <sys/param.h>
  67 #include <sys/alq.h>
  68 #include <sys/errno.h>
  69 #include <sys/eventhandler.h>
  70 #include <sys/hash.h>
  71 #include <sys/kernel.h>
  72 #include <sys/kthread.h>
  73 #include <sys/lock.h>
  74 #include <sys/mbuf.h>
  75 #include <sys/module.h>
  76 #include <sys/mutex.h>
  77 #include <sys/pcpu.h>
  78 #include <sys/proc.h>
  79 #include <sys/sbuf.h>
  80 #include <sys/sdt.h>
  81 #include <sys/smp.h>
  82 #include <sys/socket.h>
  83 #include <sys/socketvar.h>
  84 #include <sys/sysctl.h>
  85 #include <sys/unistd.h>
  86
  87 #include <net/if.h>
  88 #include <net/if_var.h>
  89 #include <net/pfil.h>
  90
  91 #include <netinet/in.h>
  92 #include <netinet/in_kdtrace.h>
  93 #include <netinet/in_pcb.h>
  94 #include <netinet/in_systm.h>
  95 #include <netinet/in_var.h>
  96 #include <netinet/ip.h>
  97 #include <netinet/ip_var.h>
  98 #include <netinet/tcp_var.h>
  99
 100 #ifdef SIFTR_IPV6
 101 #include <netinet/ip6.h>
 102 #include <netinet/ip6_var.h>
 103 #include <netinet6/in6_pcb.h>
 104 #endif /* SIFTR_IPV6 */
 105
 106 #include <machine/in_cksum.h>
 107
 108 /*
 109  * Three digit version number refers to X.Y.Z where:
 110  * X is the major version number
 111  * Y is bumped to mark backwards incompatible changes
 112  * Z is bumped to mark backwards compatible changes
 113  */
 114 #define V_MAJOR         1
 115 #define V_BACKBREAK     2
 116 #define V_BACKCOMPAT    4
 117 #define MODVERSION      __CONCAT(V_MAJOR, __CONCAT(V_BACKBREAK, V_BACKCOMPAT))
 118 #define MODVERSION_STR  __XSTRING(V_MAJOR) "." __XSTRING(V_BACKBREAK) "." \
 119     __XSTRING(V_BACKCOMPAT)
 120
 121 #define HOOK 0
 122 #define UNHOOK 1
 123 #define SIFTR_EXPECTED_MAX_TCP_FLOWS 65536
 124 #define SYS_NAME "FreeBSD"
 125 #define PACKET_TAG_SIFTR 100
 126 #define PACKET_COOKIE_SIFTR 21749576
 127 #define SIFTR_LOG_FILE_MODE 0644
 128 #define SIFTR_DISABLE 0
 129 #define SIFTR_ENABLE 1
 130
 131 /*
 132  * Hard upper limit on the length of log messages. Bump this up if you add new
 133  * data fields such that the line length could exceed the below value.
 134  */
 135 #define MAX_LOG_MSG_LEN 200
 136 /* XXX: Make this a sysctl tunable. */
 137 #define SIFTR_ALQ_BUFLEN (1000*MAX_LOG_MSG_LEN)
 138
 139 /*
 140  * 1 byte for IP version
 141  * IPv4: src/dst IP (4+4) + src/dst port (2+2) = 12 bytes
 142  * IPv6: src/dst IP (16+16) + src/dst port (2+2) = 36 bytes
 143  */
 144 #ifdef SIFTR_IPV6
 145 #define FLOW_KEY_LEN 37
 146 #else
 147 #define FLOW_KEY_LEN 13
 148 #endif
 149
 150 #ifdef SIFTR_IPV6
 151 #define SIFTR_IPMODE 6
 152 #else
 153 #define SIFTR_IPMODE 4
 154 #endif
 155
 156 /* useful macros */
 157 #define UPPER_SHORT(X)  (((X) & 0xFFFF0000) >> 16)
 158 #define LOWER_SHORT(X)  ((X) & 0x0000FFFF)
 159
 160 #define FIRST_OCTET(X)  (((X) & 0xFF000000) >> 24)
 161 #define SECOND_OCTET(X) (((X) & 0x00FF0000) >> 16)
 162 #define THIRD_OCTET(X)  (((X) & 0x0000FF00) >> 8)
 163 #define FOURTH_OCTET(X) ((X) & 0x000000FF)
 164
 165 static MALLOC_DEFINE(M_SIFTR, "siftr", "dynamic memory used by SIFTR");
 166 static MALLOC_DEFINE(M_SIFTR_PKTNODE, "siftr_pktnode",
 167     "SIFTR pkt_node struct");
 168 static MALLOC_DEFINE(M_SIFTR_HASHNODE, "siftr_hashnode",
 169     "SIFTR flow_hash_node struct");
 170
 171 /* Used as links in the pkt manager queue. */
 172 struct pkt_node {
 173         /* Timestamp of pkt as noted in the pfil hook. */
 174         struct timeval          tval;
 175         /* Direction pkt is travelling. */
 176         enum {
 177                 DIR_IN = 0,
 178                 DIR_OUT = 1,
 179         }                       direction;
 180         /* IP version pkt_node relates to; either INP_IPV4 or INP_IPV6. */
 181         uint8_t                 ipver;
 182         /* Hash of the pkt which triggered the log message. */
 183         uint32_t                hash;
 184         /* Local/foreign IP address. */
 185 #ifdef SIFTR_IPV6
 186         uint32_t                ip_laddr[4];
 187         uint32_t                ip_faddr[4];
 188 #else
 189         uint8_t                 ip_laddr[4];
 190         uint8_t                 ip_faddr[4];
 191 #endif
 192         /* Local TCP port. */
 193         uint16_t                tcp_localport;
 194         /* Foreign TCP port. */
 195         uint16_t                tcp_foreignport;
 196         /* Congestion Window (bytes). */
 197         u_long                  snd_cwnd;
 198         /* Sending Window (bytes). */
 199         u_long                  snd_wnd;
 200         /* Receive Window (bytes). */
 201         u_long                  rcv_wnd;
 202         /* Unused (was: Bandwidth Controlled Window (bytes)). */
 203         u_long                  snd_bwnd;
 204         /* Slow Start Threshold (bytes). */
 205         u_long                  snd_ssthresh;
 206         /* Current state of the TCP FSM. */
 207         int                     conn_state;
 208         /* Max Segment Size (bytes). */
 209         u_int                   max_seg_size;
 210         /*
 211          * Smoothed RTT stored as found in the TCP control block
 212          * in units of (TCP_RTT_SCALE*hz).
 213          */
 214         int                     smoothed_rtt;
 215         /* Is SACK enabled? */
 216         u_char                  sack_enabled;
 217         /* Window scaling for snd window. */
 218         u_char                  snd_scale;
 219         /* Window scaling for recv window. */
 220         u_char                  rcv_scale;
 221         /* TCP control block flags. */
 222         u_int                   flags;
 223         /* Retransmit timeout length. */
 224         int                     rxt_length;
 225         /* Size of the TCP send buffer in bytes. */
 226         u_int                   snd_buf_hiwater;
 227         /* Current num bytes in the send socket buffer. */
 228         u_int                   snd_buf_cc;
 229         /* Size of the TCP receive buffer in bytes. */
 230         u_int                   rcv_buf_hiwater;
 231         /* Current num bytes in the receive socket buffer. */
 232         u_int                   rcv_buf_cc;
 233         /* Number of bytes inflight that we are waiting on ACKs for. */
 234         u_int                   sent_inflight_bytes;
 235         /* Number of segments currently in the reassembly queue. */
 236         int                     t_segqlen;
 237         /* Flowid for the connection. */
 238         u_int                   flowid;
 239         /* Flow type for the connection. */
 240         u_int                   flowtype;
 241         /* Link to next pkt_node in the list. */
 242         STAILQ_ENTRY(pkt_node)  nodes;
 243 };
 244
 245 struct flow_hash_node
 246 {
 247         uint16_t counter;
 248         uint8_t key[FLOW_KEY_LEN];
 249         LIST_ENTRY(flow_hash_node) nodes;
 250 };
 251
 252 struct siftr_stats
 253 {
 254         /* # TCP pkts seen by the SIFTR PFIL hooks, including any skipped. */
 255         uint64_t n_in;
 256         uint64_t n_out;
 257         /* # pkts skipped due to failed malloc calls. */
 258         uint32_t nskip_in_malloc;
 259         uint32_t nskip_out_malloc;
 260         /* # pkts skipped due to failed mtx acquisition. */
 261         uint32_t nskip_in_mtx;
 262         uint32_t nskip_out_mtx;
 263         /* # pkts skipped due to failed inpcb lookups. */
 264         uint32_t nskip_in_inpcb;
 265         uint32_t nskip_out_inpcb;
 266         /* # pkts skipped due to failed tcpcb lookups. */
 267         uint32_t nskip_in_tcpcb;
 268         uint32_t nskip_out_tcpcb;
 269         /* # pkts skipped due to stack reinjection. */
 270         uint32_t nskip_in_dejavu;
 271         uint32_t nskip_out_dejavu;
 272 };
 273
 274 DPCPU_DEFINE_STATIC(struct siftr_stats, ss);
 275
 276 static volatile unsigned int siftr_exit_pkt_manager_thread = 0;
 277 static unsigned int siftr_enabled = 0;
 278 static unsigned int siftr_pkts_per_log = 1;
 279 static unsigned int siftr_generate_hashes = 0;
 280 static uint16_t     siftr_port_filter = 0;
 281 /* static unsigned int siftr_binary_log = 0; */
 282 static char siftr_logfile[PATH_MAX] = "/var/log/siftr.log";
 283 static char siftr_logfile_shadow[PATH_MAX] = "/var/log/siftr.log";
 284 static u_long siftr_hashmask;
 285 STAILQ_HEAD(pkthead, pkt_node) pkt_queue = STAILQ_HEAD_INITIALIZER(pkt_queue);
 286 LIST_HEAD(listhead, flow_hash_node) *counter_hash;
 287 static int wait_for_pkt;
 288 static struct alq *siftr_alq = NULL;
 289 static struct mtx siftr_pkt_queue_mtx;
 290 static struct mtx siftr_pkt_mgr_mtx;
 291 static struct thread *siftr_pkt_manager_thr = NULL;
 292 static char direction[2] = {'i','o'};
 293
 294 /* Required function prototypes. */
 295 static int siftr_sysctl_enabled_handler(SYSCTL_HANDLER_ARGS);
 296 static int siftr_sysctl_logfile_name_handler(SYSCTL_HANDLER_ARGS);
 297
 298 /* Declare the net.inet.siftr sysctl tree and populate it. */
 299
 300 SYSCTL_DECL(_net_inet_siftr);
 301
 302 SYSCTL_NODE(_net_inet, OID_AUTO, siftr, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
 303     "siftr related settings");
 304
 305 SYSCTL_PROC(_net_inet_siftr, OID_AUTO, enabled,
 306     CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
 307     &siftr_enabled, 0, &siftr_sysctl_enabled_handler, "IU",
 308     "switch siftr module operations on/off");
 309
 310 SYSCTL_PROC(_net_inet_siftr, OID_AUTO, logfile,
 311     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_NEEDGIANT, &siftr_logfile_shadow,
 312     sizeof(siftr_logfile_shadow), &siftr_sysctl_logfile_name_handler, "A",
 313     "file to save siftr log messages to");
 314
 315 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, ppl, CTLFLAG_RW,
 316     &siftr_pkts_per_log, 1,
 317     "number of packets between generating a log message");
 318
 319 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, genhashes, CTLFLAG_RW,
 320     &siftr_generate_hashes, 0,
 321     "enable packet hash generation");
 322
 323 SYSCTL_U16(_net_inet_siftr, OID_AUTO, port_filter, CTLFLAG_RW,
 324     &siftr_port_filter, 0,
 325     "enable packet filter on a TCP port");
 326
 327 /* XXX: TODO
 328 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, binary, CTLFLAG_RW,
 329     &siftr_binary_log, 0,
 330     "write log files in binary instead of ascii");
 331 */
 332
 333 /* Begin functions. */
 334
 335 static void
 336 siftr_process_pkt(struct pkt_node * pkt_node)
 337 {
 338         struct flow_hash_node *hash_node;
 339         struct listhead *counter_list;
 340         struct siftr_stats *ss;
 341         struct ale *log_buf;
 342         uint8_t key[FLOW_KEY_LEN];
 343         uint8_t found_match, key_offset;
 344
 345         hash_node = NULL;
 346         ss = DPCPU_PTR(ss);
 347         found_match = 0;
 348         key_offset = 1;
 349
 350         /*
 351          * Create the key that will be used to create a hash index
 352          * into our hash table. Our key consists of:
 353          * ipversion, localip, localport, foreignip, foreignport
 354          */
 355         key[0] = pkt_node->ipver;
 356         memcpy(key + key_offset, &pkt_node->ip_laddr,
 357             sizeof(pkt_node->ip_laddr));
 358         key_offset += sizeof(pkt_node->ip_laddr);
 359         memcpy(key + key_offset, &pkt_node->tcp_localport,
 360             sizeof(pkt_node->tcp_localport));
 361         key_offset += sizeof(pkt_node->tcp_localport);
 362         memcpy(key + key_offset, &pkt_node->ip_faddr,
 363             sizeof(pkt_node->ip_faddr));
 364         key_offset += sizeof(pkt_node->ip_faddr);
 365         memcpy(key + key_offset, &pkt_node->tcp_foreignport,
 366             sizeof(pkt_node->tcp_foreignport));
 367
 368         counter_list = counter_hash +
 369             (hash32_buf(key, sizeof(key), 0) & siftr_hashmask);
 370
 371         /*
 372          * If the list is not empty i.e. the hash index has
 373          * been used by another flow previously.
 374          */
 375         if (LIST_FIRST(counter_list) != NULL) {
 376                 /*
 377                  * Loop through the hash nodes in the list.
 378                  * There should normally only be 1 hash node in the list,
 379                  * except if there have been collisions at the hash index
 380                  * computed by hash32_buf().
 381                  */
 382                 LIST_FOREACH(hash_node, counter_list, nodes) {
 383                         /*
 384                          * Check if the key for the pkt we are currently
 385                          * processing is the same as the key stored in the
 386                          * hash node we are currently processing.
 387                          * If they are the same, then we've found the
 388                          * hash node that stores the counter for the flow
 389                          * the pkt belongs to.
 390                          */
 391                         if (memcmp(hash_node->key, key, sizeof(key)) == 0) {
 392                                 found_match = 1;
 393                                 break;
 394                         }
 395                 }
 396         }
 397
 398         /* If this flow hash hasn't been seen before or we have a collision. */
 399         if (hash_node == NULL || !found_match) {
 400                 /* Create a new hash node to store the flow's counter. */
 401                 hash_node = malloc(sizeof(struct flow_hash_node),
 402                     M_SIFTR_HASHNODE, M_WAITOK);
 403
 404                 if (hash_node != NULL) {
 405                         /* Initialise our new hash node list entry. */
 406                         hash_node->counter = 0;
 407                         memcpy(hash_node->key, key, sizeof(key));
 408                         LIST_INSERT_HEAD(counter_list, hash_node, nodes);
 409                 } else {
 410                         /* Malloc failed. */
 411                         if (pkt_node->direction == DIR_IN)
 412                                 ss->nskip_in_malloc++;
 413                         else
 414                                 ss->nskip_out_malloc++;
 415
 416                         return;
 417                 }
 418         } else if (siftr_pkts_per_log > 1) {
 419                 /*
 420                  * Taking the remainder of the counter divided
 421                  * by the current value of siftr_pkts_per_log
 422                  * and storing that in counter provides a neat
 423                  * way to modulate the frequency of log
 424                  * messages being written to the log file.
 425                  */
 426                 hash_node->counter = (hash_node->counter + 1) %
 427                     siftr_pkts_per_log;
 428
 429                 /*
 430                  * If we have not seen enough packets since the last time
 431                  * we wrote a log message for this connection, return.
 432                  */
 433                 if (hash_node->counter > 0)
 434                         return;
 435         }
 436
 437         log_buf = alq_getn(siftr_alq, MAX_LOG_MSG_LEN, ALQ_WAITOK);
 438
 439         if (log_buf == NULL)
 440                 return; /* Should only happen if the ALQ is shutting down. */
 441
 442 #ifdef SIFTR_IPV6
 443         pkt_node->ip_laddr[3] = ntohl(pkt_node->ip_laddr[3]);
 444         pkt_node->ip_faddr[3] = ntohl(pkt_node->ip_faddr[3]);
 445
 446         if (pkt_node->ipver == INP_IPV6) { /* IPv6 packet */
 447                 pkt_node->ip_laddr[0] = ntohl(pkt_node->ip_laddr[0]);
 448                 pkt_node->ip_laddr[1] = ntohl(pkt_node->ip_laddr[1]);
 449                 pkt_node->ip_laddr[2] = ntohl(pkt_node->ip_laddr[2]);
 450                 pkt_node->ip_faddr[0] = ntohl(pkt_node->ip_faddr[0]);
 451                 pkt_node->ip_faddr[1] = ntohl(pkt_node->ip_faddr[1]);
 452                 pkt_node->ip_faddr[2] = ntohl(pkt_node->ip_faddr[2]);
 453
 454                 /* Construct an IPv6 log message. */
 455                 log_buf->ae_bytesused = snprintf(log_buf->ae_data,
 456                     MAX_LOG_MSG_LEN,
 457                     "%c,0x%08x,%zd.%06ld,%x:%x:%x:%x:%x:%x:%x:%x,%u,%x:%x:%x:"
 458                     "%x:%x:%x:%x:%x,%u,%ld,%ld,%ld,%ld,%ld,%u,%u,%u,%u,%u,%u,"
 459                     "%u,%d,%u,%u,%u,%u,%u,%u,%u,%u\n",
 460                     direction[pkt_node->direction],
 461                     pkt_node->hash,
 462                     pkt_node->tval.tv_sec,
 463                     pkt_node->tval.tv_usec,
 464                     UPPER_SHORT(pkt_node->ip_laddr[0]),
 465                     LOWER_SHORT(pkt_node->ip_laddr[0]),
 466                     UPPER_SHORT(pkt_node->ip_laddr[1]),
 467                     LOWER_SHORT(pkt_node->ip_laddr[1]),
 468                     UPPER_SHORT(pkt_node->ip_laddr[2]),
 469                     LOWER_SHORT(pkt_node->ip_laddr[2]),
 470                     UPPER_SHORT(pkt_node->ip_laddr[3]),
 471                     LOWER_SHORT(pkt_node->ip_laddr[3]),
 472                     ntohs(pkt_node->tcp_localport),
 473                     UPPER_SHORT(pkt_node->ip_faddr[0]),
 474                     LOWER_SHORT(pkt_node->ip_faddr[0]),
 475                     UPPER_SHORT(pkt_node->ip_faddr[1]),
 476                     LOWER_SHORT(pkt_node->ip_faddr[1]),
 477                     UPPER_SHORT(pkt_node->ip_faddr[2]),
 478                     LOWER_SHORT(pkt_node->ip_faddr[2]),
 479                     UPPER_SHORT(pkt_node->ip_faddr[3]),
 480                     LOWER_SHORT(pkt_node->ip_faddr[3]),
 481                     ntohs(pkt_node->tcp_foreignport),
 482                     pkt_node->snd_ssthresh,
 483                     pkt_node->snd_cwnd,
 484                     pkt_node->snd_bwnd,
 485                     pkt_node->snd_wnd,
 486                     pkt_node->rcv_wnd,
 487                     pkt_node->snd_scale,
 488                     pkt_node->rcv_scale,
 489                     pkt_node->conn_state,
 490                     pkt_node->max_seg_size,
 491                     pkt_node->smoothed_rtt,
 492                     pkt_node->sack_enabled,
 493                     pkt_node->flags,
 494                     pkt_node->rxt_length,
 495                     pkt_node->snd_buf_hiwater,
 496                     pkt_node->snd_buf_cc,
 497                     pkt_node->rcv_buf_hiwater,
 498                     pkt_node->rcv_buf_cc,
 499                     pkt_node->sent_inflight_bytes,
 500                     pkt_node->t_segqlen,
 501                     pkt_node->flowid,
 502                     pkt_node->flowtype);
 503         } else { /* IPv4 packet */
 504                 pkt_node->ip_laddr[0] = FIRST_OCTET(pkt_node->ip_laddr[3]);
 505                 pkt_node->ip_laddr[1] = SECOND_OCTET(pkt_node->ip_laddr[3]);
 506                 pkt_node->ip_laddr[2] = THIRD_OCTET(pkt_node->ip_laddr[3]);
 507                 pkt_node->ip_laddr[3] = FOURTH_OCTET(pkt_node->ip_laddr[3]);
 508                 pkt_node->ip_faddr[0] = FIRST_OCTET(pkt_node->ip_faddr[3]);
 509                 pkt_node->ip_faddr[1] = SECOND_OCTET(pkt_node->ip_faddr[3]);
 510                 pkt_node->ip_faddr[2] = THIRD_OCTET(pkt_node->ip_faddr[3]);
 511                 pkt_node->ip_faddr[3] = FOURTH_OCTET(pkt_node->ip_faddr[3]);
 512 #endif /* SIFTR_IPV6 */
 513
 514                 /* Construct an IPv4 log message. */
 515                 log_buf->ae_bytesused = snprintf(log_buf->ae_data,
 516                     MAX_LOG_MSG_LEN,
 517                     "%c,0x%08x,%jd.%06ld,%u.%u.%u.%u,%u,%u.%u.%u.%u,%u,%ld,%ld,"
 518                     "%ld,%ld,%ld,%u,%u,%u,%u,%u,%u,%u,%d,%u,%u,%u,%u,%u,%u,%u,%u\n",
 519                     direction[pkt_node->direction],
 520                     pkt_node->hash,
 521                     (intmax_t)pkt_node->tval.tv_sec,
 522                     pkt_node->tval.tv_usec,
 523                     pkt_node->ip_laddr[0],
 524                     pkt_node->ip_laddr[1],
 525                     pkt_node->ip_laddr[2],
 526                     pkt_node->ip_laddr[3],
 527                     ntohs(pkt_node->tcp_localport),
 528                     pkt_node->ip_faddr[0],
 529                     pkt_node->ip_faddr[1],
 530                     pkt_node->ip_faddr[2],
 531                     pkt_node->ip_faddr[3],
 532                     ntohs(pkt_node->tcp_foreignport),
 533                     pkt_node->snd_ssthresh,
 534                     pkt_node->snd_cwnd,
 535                     pkt_node->snd_bwnd,
 536                     pkt_node->snd_wnd,
 537                     pkt_node->rcv_wnd,
 538                     pkt_node->snd_scale,
 539                     pkt_node->rcv_scale,
 540                     pkt_node->conn_state,
 541                     pkt_node->max_seg_size,
 542                     pkt_node->smoothed_rtt,
 543                     pkt_node->sack_enabled,
 544                     pkt_node->flags,
 545                     pkt_node->rxt_length,
 546                     pkt_node->snd_buf_hiwater,
 547                     pkt_node->snd_buf_cc,
 548                     pkt_node->rcv_buf_hiwater,
 549                     pkt_node->rcv_buf_cc,
 550                     pkt_node->sent_inflight_bytes,
 551                     pkt_node->t_segqlen,
 552                     pkt_node->flowid,
 553                     pkt_node->flowtype);
 554 #ifdef SIFTR_IPV6
 555         }
 556 #endif
 557
 558         alq_post_flags(siftr_alq, log_buf, 0);
 559 }
 560
 561 static void
 562 siftr_pkt_manager_thread(void *arg)
 563 {
 564         STAILQ_HEAD(pkthead, pkt_node) tmp_pkt_queue =
 565             STAILQ_HEAD_INITIALIZER(tmp_pkt_queue);
 566         struct pkt_node *pkt_node, *pkt_node_temp;
 567         uint8_t draining;
 568
 569         draining = 2;
 570
 571         mtx_lock(&siftr_pkt_mgr_mtx);
 572
 573         /* draining == 0 when queue has been flushed and it's safe to exit. */
 574         while (draining) {
 575                 /*
 576                  * Sleep until we are signalled to wake because thread has
 577                  * been told to exit or until 1 tick has passed.
 578                  */
 579                 mtx_sleep(&wait_for_pkt, &siftr_pkt_mgr_mtx, PWAIT, "pktwait",
 580                     1);
 581
 582                 /* Gain exclusive access to the pkt_node queue. */
 583                 mtx_lock(&siftr_pkt_queue_mtx);
 584
 585                 /*
 586                  * Move pkt_queue to tmp_pkt_queue, which leaves
 587                  * pkt_queue empty and ready to receive more pkt_nodes.
 588                  */
 589                 STAILQ_CONCAT(&tmp_pkt_queue, &pkt_queue);
 590
 591                 /*
 592                  * We've finished making changes to the list. Unlock it
 593                  * so the pfil hooks can continue queuing pkt_nodes.
 594                  */
 595                 mtx_unlock(&siftr_pkt_queue_mtx);
 596
 597                 /*
 598                  * We can't hold a mutex whilst calling siftr_process_pkt
 599                  * because ALQ might sleep waiting for buffer space.
 600                  */
 601                 mtx_unlock(&siftr_pkt_mgr_mtx);
 602
 603                 /* Flush all pkt_nodes to the log file. */
 604                 STAILQ_FOREACH_SAFE(pkt_node, &tmp_pkt_queue, nodes,
 605                     pkt_node_temp) {
 606                         siftr_process_pkt(pkt_node);
 607                         STAILQ_REMOVE_HEAD(&tmp_pkt_queue, nodes);
 608                         free(pkt_node, M_SIFTR_PKTNODE);
 609                 }
 610
 611                 KASSERT(STAILQ_EMPTY(&tmp_pkt_queue),
 612                     ("SIFTR tmp_pkt_queue not empty after flush"));
 613
 614                 mtx_lock(&siftr_pkt_mgr_mtx);
 615
 616                 /*
 617                  * If siftr_exit_pkt_manager_thread gets set during the window
 618                  * where we are draining the tmp_pkt_queue above, there might
 619                  * still be pkts in pkt_queue that need to be drained.
 620                  * Allow one further iteration to occur after
 621                  * siftr_exit_pkt_manager_thread has been set to ensure
 622                  * pkt_queue is completely empty before we kill the thread.
 623                  *
 624                  * siftr_exit_pkt_manager_thread is set only after the pfil
 625                  * hooks have been removed, so only 1 extra iteration
 626                  * is needed to drain the queue.
 627                  */
 628                 if (siftr_exit_pkt_manager_thread)
 629                         draining--;
 630         }
 631
 632         mtx_unlock(&siftr_pkt_mgr_mtx);
 633
 634         /* Calls wakeup on this thread's struct thread ptr. */
 635         kthread_exit();
 636 }
 637
 638 static uint32_t
 639 hash_pkt(struct mbuf *m, uint32_t offset)
 640 {
 641         uint32_t hash;
 642
 643         hash = 0;
 644
 645         while (m != NULL && offset > m->m_len) {
 646                 /*
 647                  * The IP packet payload does not start in this mbuf, so
 648                  * need to figure out which mbuf it starts in and what offset
 649                  * into the mbuf's data region the payload starts at.
 650                  */
 651                 offset -= m->m_len;
 652                 m = m->m_next;
 653         }
 654
 655         while (m != NULL) {
 656                 /* Ensure there is data in the mbuf */
 657                 if ((m->m_len - offset) > 0)
 658                         hash = hash32_buf(m->m_data + offset,
 659                             m->m_len - offset, hash);
 660
 661                 m = m->m_next;
 662                 offset = 0;
 663         }
 664
 665         return (hash);
 666 }
 667
 668 /*
 669  * Check if a given mbuf has the SIFTR mbuf tag. If it does, log the fact that
 670  * it's a reinjected packet and return. If it doesn't, tag the mbuf and return.
 671  * Return value >0 means the caller should skip processing this mbuf.
 672  */
 673 static inline int
 674 siftr_chkreinject(struct mbuf *m, int dir, struct siftr_stats *ss)
 675 {
 676         if (m_tag_locate(m, PACKET_COOKIE_SIFTR, PACKET_TAG_SIFTR, NULL)
 677             != NULL) {
 678                 if (dir == PFIL_IN)
 679                         ss->nskip_in_dejavu++;
 680                 else
 681                         ss->nskip_out_dejavu++;
 682
 683                 return (1);
 684         } else {
 685                 struct m_tag *tag = m_tag_alloc(PACKET_COOKIE_SIFTR,
 686                     PACKET_TAG_SIFTR, 0, M_NOWAIT);
 687                 if (tag == NULL) {
 688                         if (dir == PFIL_IN)
 689                                 ss->nskip_in_malloc++;
 690                         else
 691                                 ss->nskip_out_malloc++;
 692
 693                         return (1);
 694                 }
 695
 696                 m_tag_prepend(m, tag);
 697         }
 698
 699         return (0);
 700 }
 701
 702 /*
 703  * Look up an inpcb for a packet. Return the inpcb pointer if found, or NULL
 704  * otherwise.
 705  */
 706 static inline struct inpcb *
 707 siftr_findinpcb(int ipver, struct ip *ip, struct mbuf *m, uint16_t sport,
 708     uint16_t dport, int dir, struct siftr_stats *ss)
 709 {
 710         struct inpcb *inp;
 711
 712         /* We need the tcbinfo lock. */
 713         INP_INFO_WUNLOCK_ASSERT(&V_tcbinfo);
 714
 715         if (dir == PFIL_IN)
 716                 inp = (ipver == INP_IPV4 ?
 717                     in_pcblookup(&V_tcbinfo, ip->ip_src, sport, ip->ip_dst,
 718                     dport, INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif)
 719                     :
 720 #ifdef SIFTR_IPV6
 721                     in6_pcblookup(&V_tcbinfo,
 722                     &((struct ip6_hdr *)ip)->ip6_src, sport,
 723                     &((struct ip6_hdr *)ip)->ip6_dst, dport, INPLOOKUP_RLOCKPCB,
 724                     m->m_pkthdr.rcvif)
 725 #else
 726                     NULL
 727 #endif
 728                     );
 729
 730         else
 731                 inp = (ipver == INP_IPV4 ?
 732                     in_pcblookup(&V_tcbinfo, ip->ip_dst, dport, ip->ip_src,
 733                     sport, INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif)
 734                     :
 735 #ifdef SIFTR_IPV6
 736                     in6_pcblookup(&V_tcbinfo,
 737                     &((struct ip6_hdr *)ip)->ip6_dst, dport,
 738                     &((struct ip6_hdr *)ip)->ip6_src, sport, INPLOOKUP_RLOCKPCB,
 739                     m->m_pkthdr.rcvif)
 740 #else
 741                     NULL
 742 #endif
 743                     );
 744
 745         /* If we can't find the inpcb, bail. */
 746         if (inp == NULL) {
 747                 if (dir == PFIL_IN)
 748                         ss->nskip_in_inpcb++;
 749                 else
 750                         ss->nskip_out_inpcb++;
 751         }
 752
 753         return (inp);
 754 }
 755
 756 static inline void
 757 siftr_siftdata(struct pkt_node *pn, struct inpcb *inp, struct tcpcb *tp,
 758     int ipver, int dir, int inp_locally_locked)
 759 {
 760 #ifdef SIFTR_IPV6
 761         if (ipver == INP_IPV4) {
 762                 pn->ip_laddr[3] = inp->inp_laddr.s_addr;
 763                 pn->ip_faddr[3] = inp->inp_faddr.s_addr;
 764 #else
 765                 *((uint32_t *)pn->ip_laddr) = inp->inp_laddr.s_addr;
 766                 *((uint32_t *)pn->ip_faddr) = inp->inp_faddr.s_addr;
 767 #endif
 768 #ifdef SIFTR_IPV6
 769         } else {
 770                 pn->ip_laddr[0] = inp->in6p_laddr.s6_addr32[0];
 771                 pn->ip_laddr[1] = inp->in6p_laddr.s6_addr32[1];
 772                 pn->ip_laddr[2] = inp->in6p_laddr.s6_addr32[2];
 773                 pn->ip_laddr[3] = inp->in6p_laddr.s6_addr32[3];
 774                 pn->ip_faddr[0] = inp->in6p_faddr.s6_addr32[0];
 775                 pn->ip_faddr[1] = inp->in6p_faddr.s6_addr32[1];
 776                 pn->ip_faddr[2] = inp->in6p_faddr.s6_addr32[2];
 777                 pn->ip_faddr[3] = inp->in6p_faddr.s6_addr32[3];
 778         }
 779 #endif
 780         pn->tcp_localport = inp->inp_lport;
 781         pn->tcp_foreignport = inp->inp_fport;
 782         pn->snd_cwnd = tp->snd_cwnd;
 783         pn->snd_wnd = tp->snd_wnd;
 784         pn->rcv_wnd = tp->rcv_wnd;
 785         pn->snd_bwnd = 0;               /* Unused, kept for compat. */
 786         pn->snd_ssthresh = tp->snd_ssthresh;
 787         pn->snd_scale = tp->snd_scale;
 788         pn->rcv_scale = tp->rcv_scale;
 789         pn->conn_state = tp->t_state;
 790         pn->max_seg_size = tp->t_maxseg;
 791         pn->smoothed_rtt = tp->t_srtt;
 792         pn->sack_enabled = (tp->t_flags & TF_SACK_PERMIT) != 0;
 793         pn->flags = tp->t_flags;
 794         pn->rxt_length = tp->t_rxtcur;
 795         pn->snd_buf_hiwater = inp->inp_socket->so_snd.sb_hiwat;
 796         pn->snd_buf_cc = sbused(&inp->inp_socket->so_snd);
 797         pn->rcv_buf_hiwater = inp->inp_socket->so_rcv.sb_hiwat;
 798         pn->rcv_buf_cc = sbused(&inp->inp_socket->so_rcv);
 799         pn->sent_inflight_bytes = tp->snd_max - tp->snd_una;
 800         pn->t_segqlen = tp->t_segqlen;
 801         pn->flowid = inp->inp_flowid;
 802         pn->flowtype = inp->inp_flowtype;
 803
 804         /* We've finished accessing the tcb so release the lock. */
 805         if (inp_locally_locked)
 806                 INP_RUNLOCK(inp);
 807
 808         pn->ipver = ipver;
 809         pn->direction = (dir == PFIL_IN ? DIR_IN : DIR_OUT);
 810
 811         /*
 812          * Significantly more accurate than using getmicrotime(), but slower!
 813          * Gives true microsecond resolution at the expense of a hit to
 814          * maximum pps throughput processing when SIFTR is loaded and enabled.
 815          */
 816         microtime(&pn->tval);
 817         TCP_PROBE1(siftr, &pn);
 818
 819 }
 820
 821 /*
 822  * pfil hook that is called for each IPv4 packet making its way through the
 823  * stack in either direction.
 824  * The pfil subsystem holds a non-sleepable mutex somewhere when
 825  * calling our hook function, so we can't sleep at all.
 826  * It's very important to use the M_NOWAIT flag with all function calls
 827  * that support it so that they won't sleep, otherwise you get a panic.
 828  */
 829 static pfil_return_t
 830 siftr_chkpkt(struct mbuf **m, struct ifnet *ifp, int flags,
 831     void *ruleset __unused, struct inpcb *inp)
 832 {
 833         struct pkt_node *pn;
 834         struct ip *ip;
 835         struct tcphdr *th;
 836         struct tcpcb *tp;
 837         struct siftr_stats *ss;
 838         unsigned int ip_hl;
 839         int inp_locally_locked, dir;
 840
 841         inp_locally_locked = 0;
 842         dir = PFIL_DIR(flags);
 843         ss = DPCPU_PTR(ss);
 844
 845         /*
 846          * m_pullup is not required here because ip_{input|output}
 847          * already do the heavy lifting for us.
 848          */
 849
 850         ip = mtod(*m, struct ip *);
 851
 852         /* Only continue processing if the packet is TCP. */
 853         if (ip->ip_p != IPPROTO_TCP)
 854                 goto ret;
 855
 856         /*
 857          * If a kernel subsystem reinjects packets into the stack, our pfil
 858          * hook will be called multiple times for the same packet.
 859          * Make sure we only process unique packets.
 860          */
 861         if (siftr_chkreinject(*m, dir, ss))
 862                 goto ret;
 863
 864         if (dir == PFIL_IN)
 865                 ss->n_in++;
 866         else
 867                 ss->n_out++;
 868
 869         /*
 870          * Create a tcphdr struct starting at the correct offset
 871          * in the IP packet. ip->ip_hl gives the ip header length
 872          * in 4-byte words, so multiply it to get the size in bytes.
 873          */
 874         ip_hl = (ip->ip_hl << 2);
 875         th = (struct tcphdr *)((caddr_t)ip + ip_hl);
 876
 877         /*
 878          * If the pfil hooks don't provide a pointer to the
 879          * inpcb, we need to find it ourselves and lock it.
 880          */
 881         if (!inp) {
 882                 /* Find the corresponding inpcb for this pkt. */
 883                 inp = siftr_findinpcb(INP_IPV4, ip, *m, th->th_sport,
 884                     th->th_dport, dir, ss);
 885
 886                 if (inp == NULL)
 887                         goto ret;
 888                 else
 889                         inp_locally_locked = 1;
 890         }
 891
 892         INP_LOCK_ASSERT(inp);
 893
 894         /* Find the TCP control block that corresponds with this packet */
 895         tp = intotcpcb(inp);
 896
 897         /*
 898          * If we can't find the TCP control block (happens occasionaly for a
 899          * packet sent during the shutdown phase of a TCP connection),
 900          * or we're in the timewait state, bail
 901          */
 902         if (tp == NULL || inp->inp_flags & INP_TIMEWAIT) {
 903                 if (dir == PFIL_IN)
 904                         ss->nskip_in_tcpcb++;
 905                 else
 906                         ss->nskip_out_tcpcb++;
 907
 908                 goto inp_unlock;
 909         }
 910
 911         /*
 912          * Only pkts selected by the tcp port filter
 913          * can be inserted into the pkt_queue
 914          */
 915         if ((siftr_port_filter != 0) &&
 916             (siftr_port_filter != ntohs(inp->inp_lport)) &&
 917             (siftr_port_filter != ntohs(inp->inp_fport))) {
 918                 goto inp_unlock;
 919         }
 920
 921         pn = malloc(sizeof(struct pkt_node), M_SIFTR_PKTNODE, M_NOWAIT|M_ZERO);
 922
 923         if (pn == NULL) {
 924                 if (dir == PFIL_IN)
 925                         ss->nskip_in_malloc++;
 926                 else
 927                         ss->nskip_out_malloc++;
 928
 929                 goto inp_unlock;
 930         }
 931
 932         siftr_siftdata(pn, inp, tp, INP_IPV4, dir, inp_locally_locked);
 933
 934         if (siftr_generate_hashes) {
 935                 if ((*m)->m_pkthdr.csum_flags & CSUM_TCP) {
 936                         /*
 937                          * For outbound packets, the TCP checksum isn't
 938                          * calculated yet. This is a problem for our packet
 939                          * hashing as the receiver will calc a different hash
 940                          * to ours if we don't include the correct TCP checksum
 941                          * in the bytes being hashed. To work around this
 942                          * problem, we manually calc the TCP checksum here in
 943                          * software. We unset the CSUM_TCP flag so the lower
 944                          * layers don't recalc it.
 945                          */
 946                         (*m)->m_pkthdr.csum_flags &= ~CSUM_TCP;
 947
 948                         /*
 949                          * Calculate the TCP checksum in software and assign
 950                          * to correct TCP header field, which will follow the
 951                          * packet mbuf down the stack. The trick here is that
 952                          * tcp_output() sets th->th_sum to the checksum of the
 953                          * pseudo header for us already. Because of the nature
 954                          * of the checksumming algorithm, we can sum over the
 955                          * entire IP payload (i.e. TCP header and data), which
 956                          * will include the already calculated pseduo header
 957                          * checksum, thus giving us the complete TCP checksum.
 958                          *
 959                          * To put it in simple terms, if checksum(1,2,3,4)=10,
 960                          * then checksum(1,2,3,4,5) == checksum(10,5).
 961                          * This property is what allows us to "cheat" and
 962                          * checksum only the IP payload which has the TCP
 963                          * th_sum field populated with the pseudo header's
 964                          * checksum, and not need to futz around checksumming
 965                          * pseudo header bytes and TCP header/data in one hit.
 966                          * Refer to RFC 1071 for more info.
 967                          *
 968                          * NB: in_cksum_skip(struct mbuf *m, int len, int skip)
 969                          * in_cksum_skip 2nd argument is NOT the number of
 970                          * bytes to read from the mbuf at "skip" bytes offset
 971                          * from the start of the mbuf (very counter intuitive!).
 972                          * The number of bytes to read is calculated internally
 973                          * by the function as len-skip i.e. to sum over the IP
 974                          * payload (TCP header + data) bytes, it is INCORRECT
 975                          * to call the function like this:
 976                          * in_cksum_skip(at, ip->ip_len - offset, offset)
 977                          * Rather, it should be called like this:
 978                          * in_cksum_skip(at, ip->ip_len, offset)
 979                          * which means read "ip->ip_len - offset" bytes from
 980                          * the mbuf cluster "at" at offset "offset" bytes from
 981                          * the beginning of the "at" mbuf's data pointer.
 982                          */
 983                         th->th_sum = in_cksum_skip(*m, ntohs(ip->ip_len),
 984                             ip_hl);
 985                 }
 986
 987                 /*
 988                  * XXX: Having to calculate the checksum in software and then
 989                  * hash over all bytes is really inefficient. Would be nice to
 990                  * find a way to create the hash and checksum in the same pass
 991                  * over the bytes.
 992                  */
 993                 pn->hash = hash_pkt(*m, ip_hl);
 994         }
 995
 996         mtx_lock(&siftr_pkt_queue_mtx);
 997         STAILQ_INSERT_TAIL(&pkt_queue, pn, nodes);
 998         mtx_unlock(&siftr_pkt_queue_mtx);
 999         goto ret;
1000
1001 inp_unlock:
1002         if (inp_locally_locked)
1003                 INP_RUNLOCK(inp);
1004
1005 ret:
1006         return (PFIL_PASS);
1007 }
1008
1009 #ifdef SIFTR_IPV6
1010 static int
1011 siftr_chkpkt6(struct mbuf **m, struct ifnet *ifp, int flags, struct inpcb *inp)
1012 {
1013         struct pkt_node *pn;
1014         struct ip6_hdr *ip6;
1015         struct tcphdr *th;
1016         struct tcpcb *tp;
1017         struct siftr_stats *ss;
1018         unsigned int ip6_hl;
1019         int inp_locally_locked, dir;
1020
1021         inp_locally_locked = 0;
1022         dir = PFIL_DIR(flags);
1023         ss = DPCPU_PTR(ss);
1024
1025         /*
1026          * m_pullup is not required here because ip6_{input|output}
1027          * already do the heavy lifting for us.
1028          */
1029
1030         ip6 = mtod(*m, struct ip6_hdr *);
1031
1032         /*
1033          * Only continue processing if the packet is TCP
1034          * XXX: We should follow the next header fields
1035          * as shown on Pg 6 RFC 2460, but right now we'll
1036          * only check pkts that have no extension headers.
1037          */
1038         if (ip6->ip6_nxt != IPPROTO_TCP)
1039                 goto ret6;
1040
1041         /*
1042          * If a kernel subsystem reinjects packets into the stack, our pfil
1043          * hook will be called multiple times for the same packet.
1044          * Make sure we only process unique packets.
1045          */
1046         if (siftr_chkreinject(*m, dir, ss))
1047                 goto ret6;
1048
1049         if (dir == PFIL_IN)
1050                 ss->n_in++;
1051         else
1052                 ss->n_out++;
1053
1054         ip6_hl = sizeof(struct ip6_hdr);
1055
1056         /*
1057          * Create a tcphdr struct starting at the correct offset
1058          * in the ipv6 packet. ip->ip_hl gives the ip header length
1059          * in 4-byte words, so multiply it to get the size in bytes.
1060          */
1061         th = (struct tcphdr *)((caddr_t)ip6 + ip6_hl);
1062
1063         /*
1064          * For inbound packets, the pfil hooks don't provide a pointer to the
1065          * inpcb, so we need to find it ourselves and lock it.
1066          */
1067         if (!inp) {
1068                 /* Find the corresponding inpcb for this pkt. */
1069                 inp = siftr_findinpcb(INP_IPV6, (struct ip *)ip6, *m,
1070                     th->th_sport, th->th_dport, dir, ss);
1071
1072                 if (inp == NULL)
1073                         goto ret6;
1074                 else
1075                         inp_locally_locked = 1;
1076         }
1077
1078         /* Find the TCP control block that corresponds with this packet. */
1079         tp = intotcpcb(inp);
1080
1081         /*
1082          * If we can't find the TCP control block (happens occasionaly for a
1083          * packet sent during the shutdown phase of a TCP connection),
1084          * or we're in the timewait state, bail.
1085          */
1086         if (tp == NULL || inp->inp_flags & INP_TIMEWAIT) {
1087                 if (dir == PFIL_IN)
1088                         ss->nskip_in_tcpcb++;
1089                 else
1090                         ss->nskip_out_tcpcb++;
1091
1092                 goto inp_unlock6;
1093         }
1094
1095         /*
1096          * Only pkts selected by the tcp port filter
1097          * can be inserted into the pkt_queue
1098          */
1099         if ((siftr_port_filter != 0) &&
1100             (siftr_port_filter != ntohs(inp->inp_lport)) &&
1101             (siftr_port_filter != ntohs(inp->inp_fport))) {
1102                 goto inp_unlock6;
1103         }
1104
1105         pn = malloc(sizeof(struct pkt_node), M_SIFTR_PKTNODE, M_NOWAIT|M_ZERO);
1106
1107         if (pn == NULL) {
1108                 if (dir == PFIL_IN)
1109                         ss->nskip_in_malloc++;
1110                 else
1111                         ss->nskip_out_malloc++;
1112
1113                 goto inp_unlock6;
1114         }
1115
1116         siftr_siftdata(pn, inp, tp, INP_IPV6, dir, inp_locally_locked);
1117
1118         /* XXX: Figure out how to generate hashes for IPv6 packets. */
1119
1120         mtx_lock(&siftr_pkt_queue_mtx);
1121         STAILQ_INSERT_TAIL(&pkt_queue, pn, nodes);
1122         mtx_unlock(&siftr_pkt_queue_mtx);
1123         goto ret6;
1124
1125 inp_unlock6:
1126         if (inp_locally_locked)
1127                 INP_RUNLOCK(inp);
1128
1129 ret6:
1130         /* Returning 0 ensures pfil will not discard the pkt. */
1131         return (0);
1132 }
1133 #endif /* #ifdef SIFTR_IPV6 */
1134
1135 VNET_DEFINE_STATIC(pfil_hook_t, siftr_inet_hook);
1136 #define V_siftr_inet_hook       VNET(siftr_inet_hook)
1137 #ifdef INET6
1138 VNET_DEFINE_STATIC(pfil_hook_t, siftr_inet6_hook);
1139 #define V_siftr_inet6_hook      VNET(siftr_inet6_hook)
1140 #endif
1141 static int
1142 siftr_pfil(int action)
1143 {
1144         struct pfil_hook_args pha;
1145         struct pfil_link_args pla;
1146
1147         pha.pa_version = PFIL_VERSION;
1148         pha.pa_flags = PFIL_IN | PFIL_OUT;
1149         pha.pa_modname = "siftr";
1150         pha.pa_ruleset = NULL;
1151         pha.pa_rulname = "default";
1152
1153         pla.pa_version = PFIL_VERSION;
1154         pla.pa_flags = PFIL_IN | PFIL_OUT |
1155             PFIL_HEADPTR | PFIL_HOOKPTR;
1156
1157         VNET_ITERATOR_DECL(vnet_iter);
1158
1159         VNET_LIST_RLOCK();
1160         VNET_FOREACH(vnet_iter) {
1161                 CURVNET_SET(vnet_iter);
1162
1163                 if (action == HOOK) {
1164                         pha.pa_func = siftr_chkpkt;
1165                         pha.pa_type = PFIL_TYPE_IP4;
1166                         V_siftr_inet_hook = pfil_add_hook(&pha);
1167                         pla.pa_hook = V_siftr_inet_hook;
1168                         pla.pa_head = V_inet_pfil_head;
1169                         (void)pfil_link(&pla);
1170 #ifdef SIFTR_IPV6
1171                         pha.pa_func = siftr_chkpkt6;
1172                         pha.pa_type = PFIL_TYPE_IP6;
1173                         V_siftr_inet6_hook = pfil_add_hook(&pha);
1174                         pla.pa_hook = V_siftr_inet6_hook;
1175                         pla.pa_head = V_inet6_pfil_head;
1176                         (void)pfil_link(&pla);
1177 #endif
1178                 } else if (action == UNHOOK) {
1179                         pfil_remove_hook(V_siftr_inet_hook);
1180 #ifdef SIFTR_IPV6
1181                         pfil_remove_hook(V_siftr_inet6_hook);
1182 #endif
1183                 }
1184                 CURVNET_RESTORE();
1185         }
1186         VNET_LIST_RUNLOCK();
1187
1188         return (0);
1189 }
1190
1191 static int
1192 siftr_sysctl_logfile_name_handler(SYSCTL_HANDLER_ARGS)
1193 {
1194         struct alq *new_alq;
1195         int error;
1196
1197         error = sysctl_handle_string(oidp, arg1, arg2, req);
1198
1199         /* Check for error or same filename */
1200         if (error != 0 || req->newptr == NULL ||
1201             strncmp(siftr_logfile, arg1, arg2) == 0)
1202                 goto done;
1203
1204         /* Filname changed */
1205         error = alq_open(&new_alq, arg1, curthread->td_ucred,
1206             SIFTR_LOG_FILE_MODE, SIFTR_ALQ_BUFLEN, 0);
1207         if (error != 0)
1208                 goto done;
1209
1210         /*
1211          * If disabled, siftr_alq == NULL so we simply close
1212          * the alq as we've proved it can be opened.
1213          * If enabled, close the existing alq and switch the old
1214          * for the new.
1215          */
1216         if (siftr_alq == NULL) {
1217                 alq_close(new_alq);
1218         } else {
1219                 alq_close(siftr_alq);
1220                 siftr_alq = new_alq;
1221         }
1222
1223         /* Update filename upon success */
1224         strlcpy(siftr_logfile, arg1, arg2);
1225 done:
1226         return (error);
1227 }
1228
1229 static int
1230 siftr_manage_ops(uint8_t action)
1231 {
1232         struct siftr_stats totalss;
1233         struct timeval tval;
1234         struct flow_hash_node *counter, *tmp_counter;
1235         struct sbuf *s;
1236         int i, key_index, error;
1237         uint32_t bytes_to_write, total_skipped_pkts;
1238         uint16_t lport, fport;
1239         uint8_t *key, ipver __unused;
1240
1241 #ifdef SIFTR_IPV6
1242         uint32_t laddr[4];
1243         uint32_t faddr[4];
1244 #else
1245         uint8_t laddr[4];
1246         uint8_t faddr[4];
1247 #endif
1248
1249         error = 0;
1250         total_skipped_pkts = 0;
1251
1252         /* Init an autosizing sbuf that initially holds 200 chars. */
1253         if ((s = sbuf_new(NULL, NULL, 200, SBUF_AUTOEXTEND)) == NULL)
1254                 return (-1);
1255
1256         if (action == SIFTR_ENABLE && siftr_pkt_manager_thr == NULL) {
1257                 /*
1258                  * Create our alq
1259                  * XXX: We should abort if alq_open fails!
1260                  */
1261                 alq_open(&siftr_alq, siftr_logfile, curthread->td_ucred,
1262                     SIFTR_LOG_FILE_MODE, SIFTR_ALQ_BUFLEN, 0);
1263
1264                 STAILQ_INIT(&pkt_queue);
1265
1266                 DPCPU_ZERO(ss);
1267
1268                 siftr_exit_pkt_manager_thread = 0;
1269
1270                 kthread_add(&siftr_pkt_manager_thread, NULL, NULL,
1271                     &siftr_pkt_manager_thr, RFNOWAIT, 0,
1272                     "siftr_pkt_manager_thr");
1273
1274                 siftr_pfil(HOOK);
1275
1276                 microtime(&tval);
1277
1278                 sbuf_printf(s,
1279                     "enable_time_secs=%jd\tenable_time_usecs=%06ld\t"
1280                     "siftrver=%s\thz=%u\ttcp_rtt_scale=%u\tsysname=%s\t"
1281                     "sysver=%u\tipmode=%u\n",
1282                     (intmax_t)tval.tv_sec, tval.tv_usec, MODVERSION_STR, hz,
1283                     TCP_RTT_SCALE, SYS_NAME, __FreeBSD_version, SIFTR_IPMODE);
1284
1285                 sbuf_finish(s);
1286                 alq_writen(siftr_alq, sbuf_data(s), sbuf_len(s), ALQ_WAITOK);
1287
1288         } else if (action == SIFTR_DISABLE && siftr_pkt_manager_thr != NULL) {
1289                 /*
1290                  * Remove the pfil hook functions. All threads currently in
1291                  * the hook functions are allowed to exit before siftr_pfil()
1292                  * returns.
1293                  */
1294                 siftr_pfil(UNHOOK);
1295
1296                 /* This will block until the pkt manager thread unlocks it. */
1297                 mtx_lock(&siftr_pkt_mgr_mtx);
1298
1299                 /* Tell the pkt manager thread that it should exit now. */
1300                 siftr_exit_pkt_manager_thread = 1;
1301
1302                 /*
1303                  * Wake the pkt_manager thread so it realises that
1304                  * siftr_exit_pkt_manager_thread == 1 and exits gracefully.
1305                  * The wakeup won't be delivered until we unlock
1306                  * siftr_pkt_mgr_mtx so this isn't racy.
1307                  */
1308                 wakeup(&wait_for_pkt);
1309
1310                 /* Wait for the pkt_manager thread to exit. */
1311                 mtx_sleep(siftr_pkt_manager_thr, &siftr_pkt_mgr_mtx, PWAIT,
1312                     "thrwait", 0);
1313
1314                 siftr_pkt_manager_thr = NULL;
1315                 mtx_unlock(&siftr_pkt_mgr_mtx);
1316
1317                 totalss.n_in = DPCPU_VARSUM(ss, n_in);
1318                 totalss.n_out = DPCPU_VARSUM(ss, n_out);
1319                 totalss.nskip_in_malloc = DPCPU_VARSUM(ss, nskip_in_malloc);
1320                 totalss.nskip_out_malloc = DPCPU_VARSUM(ss, nskip_out_malloc);
1321                 totalss.nskip_in_mtx = DPCPU_VARSUM(ss, nskip_in_mtx);
1322                 totalss.nskip_out_mtx = DPCPU_VARSUM(ss, nskip_out_mtx);
1323                 totalss.nskip_in_tcpcb = DPCPU_VARSUM(ss, nskip_in_tcpcb);
1324                 totalss.nskip_out_tcpcb = DPCPU_VARSUM(ss, nskip_out_tcpcb);
1325                 totalss.nskip_in_inpcb = DPCPU_VARSUM(ss, nskip_in_inpcb);
1326                 totalss.nskip_out_inpcb = DPCPU_VARSUM(ss, nskip_out_inpcb);
1327
1328                 total_skipped_pkts = totalss.nskip_in_malloc +
1329                     totalss.nskip_out_malloc + totalss.nskip_in_mtx +
1330                     totalss.nskip_out_mtx + totalss.nskip_in_tcpcb +
1331                     totalss.nskip_out_tcpcb + totalss.nskip_in_inpcb +
1332                     totalss.nskip_out_inpcb;
1333
1334                 microtime(&tval);
1335
1336                 sbuf_printf(s,
1337                     "disable_time_secs=%jd\tdisable_time_usecs=%06ld\t"
1338                     "num_inbound_tcp_pkts=%ju\tnum_outbound_tcp_pkts=%ju\t"
1339                     "total_tcp_pkts=%ju\tnum_inbound_skipped_pkts_malloc=%u\t"
1340                     "num_outbound_skipped_pkts_malloc=%u\t"
1341                     "num_inbound_skipped_pkts_mtx=%u\t"
1342                     "num_outbound_skipped_pkts_mtx=%u\t"
1343                     "num_inbound_skipped_pkts_tcpcb=%u\t"
1344                     "num_outbound_skipped_pkts_tcpcb=%u\t"
1345                     "num_inbound_skipped_pkts_inpcb=%u\t"
1346                     "num_outbound_skipped_pkts_inpcb=%u\t"
1347                     "total_skipped_tcp_pkts=%u\tflow_list=",
1348                     (intmax_t)tval.tv_sec,
1349                     tval.tv_usec,
1350                     (uintmax_t)totalss.n_in,
1351                     (uintmax_t)totalss.n_out,
1352                     (uintmax_t)(totalss.n_in + totalss.n_out),
1353                     totalss.nskip_in_malloc,
1354                     totalss.nskip_out_malloc,
1355                     totalss.nskip_in_mtx,
1356                     totalss.nskip_out_mtx,
1357                     totalss.nskip_in_tcpcb,
1358                     totalss.nskip_out_tcpcb,
1359                     totalss.nskip_in_inpcb,
1360                     totalss.nskip_out_inpcb,
1361                     total_skipped_pkts);
1362
1363                 /*
1364                  * Iterate over the flow hash, printing a summary of each
1365                  * flow seen and freeing any malloc'd memory.
1366                  * The hash consists of an array of LISTs (man 3 queue).
1367                  */
1368                 for (i = 0; i <= siftr_hashmask; i++) {
1369                         LIST_FOREACH_SAFE(counter, counter_hash + i, nodes,
1370                             tmp_counter) {
1371                                 key = counter->key;
1372                                 key_index = 1;
1373
1374                                 ipver = key[0];
1375
1376                                 memcpy(laddr, key + key_index, sizeof(laddr));
1377                                 key_index += sizeof(laddr);
1378                                 memcpy(&lport, key + key_index, sizeof(lport));
1379                                 key_index += sizeof(lport);
1380                                 memcpy(faddr, key + key_index, sizeof(faddr));
1381                                 key_index += sizeof(faddr);
1382                                 memcpy(&fport, key + key_index, sizeof(fport));
1383
1384 #ifdef SIFTR_IPV6
1385                                 laddr[3] = ntohl(laddr[3]);
1386                                 faddr[3] = ntohl(faddr[3]);
1387
1388                                 if (ipver == INP_IPV6) {
1389                                         laddr[0] = ntohl(laddr[0]);
1390                                         laddr[1] = ntohl(laddr[1]);
1391                                         laddr[2] = ntohl(laddr[2]);
1392                                         faddr[0] = ntohl(faddr[0]);
1393                                         faddr[1] = ntohl(faddr[1]);
1394                                         faddr[2] = ntohl(faddr[2]);
1395
1396                                         sbuf_printf(s,
1397                                             "%x:%x:%x:%x:%x:%x:%x:%x;%u-"
1398                                             "%x:%x:%x:%x:%x:%x:%x:%x;%u,",
1399                                             UPPER_SHORT(laddr[0]),
1400                                             LOWER_SHORT(laddr[0]),
1401                                             UPPER_SHORT(laddr[1]),
1402                                             LOWER_SHORT(laddr[1]),
1403                                             UPPER_SHORT(laddr[2]),
1404                                             LOWER_SHORT(laddr[2]),
1405                                             UPPER_SHORT(laddr[3]),
1406                                             LOWER_SHORT(laddr[3]),
1407                                             ntohs(lport),
1408                                             UPPER_SHORT(faddr[0]),
1409                                             LOWER_SHORT(faddr[0]),
1410                                             UPPER_SHORT(faddr[1]),
1411                                             LOWER_SHORT(faddr[1]),
1412                                             UPPER_SHORT(faddr[2]),
1413                                             LOWER_SHORT(faddr[2]),
1414                                             UPPER_SHORT(faddr[3]),
1415                                             LOWER_SHORT(faddr[3]),
1416                                             ntohs(fport));
1417                                 } else {
1418                                         laddr[0] = FIRST_OCTET(laddr[3]);
1419                                         laddr[1] = SECOND_OCTET(laddr[3]);
1420                                         laddr[2] = THIRD_OCTET(laddr[3]);
1421                                         laddr[3] = FOURTH_OCTET(laddr[3]);
1422                                         faddr[0] = FIRST_OCTET(faddr[3]);
1423                                         faddr[1] = SECOND_OCTET(faddr[3]);
1424                                         faddr[2] = THIRD_OCTET(faddr[3]);
1425                                         faddr[3] = FOURTH_OCTET(faddr[3]);
1426 #endif
1427                                         sbuf_printf(s,
1428                                             "%u.%u.%u.%u;%u-%u.%u.%u.%u;%u,",
1429                                             laddr[0],
1430                                             laddr[1],
1431                                             laddr[2],
1432                                             laddr[3],
1433                                             ntohs(lport),
1434                                             faddr[0],
1435                                             faddr[1],
1436                                             faddr[2],
1437                                             faddr[3],
1438                                             ntohs(fport));
1439 #ifdef SIFTR_IPV6
1440                                 }
1441 #endif
1442
1443                                 free(counter, M_SIFTR_HASHNODE);
1444                         }
1445
1446                         LIST_INIT(counter_hash + i);
1447                 }
1448
1449                 sbuf_printf(s, "\n");
1450                 sbuf_finish(s);
1451
1452                 i = 0;
1453                 do {
1454                         bytes_to_write = min(SIFTR_ALQ_BUFLEN, sbuf_len(s)-i);
1455                         alq_writen(siftr_alq, sbuf_data(s)+i, bytes_to_write, ALQ_WAITOK);
1456                         i += bytes_to_write;
1457                 } while (i < sbuf_len(s));
1458
1459                 alq_close(siftr_alq);
1460                 siftr_alq = NULL;
1461         } else
1462                 error = EINVAL;
1463
1464         sbuf_delete(s);
1465
1466         /*
1467          * XXX: Should be using ret to check if any functions fail
1468          * and set error appropriately
1469          */
1470
1471         return (error);
1472 }
1473
1474 static int
1475 siftr_sysctl_enabled_handler(SYSCTL_HANDLER_ARGS)
1476 {
1477         int error;
1478         uint32_t new;
1479
1480         new = siftr_enabled;
1481         error = sysctl_handle_int(oidp, &new, 0, req);
1482         if (error == 0 && req->newptr != NULL) {
1483                 if (new > 1)
1484                         return (EINVAL);
1485                 else if (new != siftr_enabled) {
1486                         if ((error = siftr_manage_ops(new)) == 0) {
1487                                 siftr_enabled = new;
1488                         } else {
1489                                 siftr_manage_ops(SIFTR_DISABLE);
1490                         }
1491                 }
1492         }
1493
1494         return (error);
1495 }
1496
1497 static void
1498 siftr_shutdown_handler(void *arg)
1499 {
1500         if (siftr_enabled == 1) {
1501                 siftr_manage_ops(SIFTR_DISABLE);
1502         }
1503 }
1504
1505 /*
1506  * Module is being unloaded or machine is shutting down. Take care of cleanup.
1507  */
1508 static int
1509 deinit_siftr(void)
1510 {
1511         /* Cleanup. */
1512         siftr_manage_ops(SIFTR_DISABLE);
1513         hashdestroy(counter_hash, M_SIFTR, siftr_hashmask);
1514         mtx_destroy(&siftr_pkt_queue_mtx);
1515         mtx_destroy(&siftr_pkt_mgr_mtx);
1516
1517         return (0);
1518 }
1519
1520 /*
1521  * Module has just been loaded into the kernel.
1522  */
1523 static int
1524 init_siftr(void)
1525 {
1526         EVENTHANDLER_REGISTER(shutdown_pre_sync, siftr_shutdown_handler, NULL,
1527             SHUTDOWN_PRI_FIRST);
1528
1529         /* Initialise our flow counter hash table. */
1530         counter_hash = hashinit(SIFTR_EXPECTED_MAX_TCP_FLOWS, M_SIFTR,
1531             &siftr_hashmask);
1532
1533         mtx_init(&siftr_pkt_queue_mtx, "siftr_pkt_queue_mtx", NULL, MTX_DEF);
1534         mtx_init(&siftr_pkt_mgr_mtx, "siftr_pkt_mgr_mtx", NULL, MTX_DEF);
1535
1536         /* Print message to the user's current terminal. */
1537         uprintf("\nStatistical Information For TCP Research (SIFTR) %s\n"
1538             "          http://caia.swin.edu.au/urp/newtcp\n\n",
1539             MODVERSION_STR);
1540
1541         return (0);
1542 }
1543
1544 /*
1545  * This is the function that is called to load and unload the module.
1546  * When the module is loaded, this function is called once with
1547  * "what" == MOD_LOAD
1548  * When the module is unloaded, this function is called twice with
1549  * "what" = MOD_QUIESCE first, followed by "what" = MOD_UNLOAD second
1550  * When the system is shut down e.g. CTRL-ALT-DEL or using the shutdown command,
1551  * this function is called once with "what" = MOD_SHUTDOWN
1552  * When the system is shut down, the handler isn't called until the very end
1553  * of the shutdown sequence i.e. after the disks have been synced.
1554  */
1555 static int
1556 siftr_load_handler(module_t mod, int what, void *arg)
1557 {
1558         int ret;
1559
1560         switch (what) {
1561         case MOD_LOAD:
1562                 ret = init_siftr();
1563                 break;
1564
1565         case MOD_QUIESCE:
1566         case MOD_SHUTDOWN:
1567                 ret = deinit_siftr();
1568                 break;
1569
1570         case MOD_UNLOAD:
1571                 ret = 0;
1572                 break;
1573
1574         default:
1575                 ret = EINVAL;
1576                 break;
1577         }
1578
1579         return (ret);
1580 }
1581
1582 static moduledata_t siftr_mod = {
1583         .name = "siftr",
1584         .evhand = siftr_load_handler,
1585 };
1586
1587 /*
1588  * Param 1: name of the kernel module
1589  * Param 2: moduledata_t struct containing info about the kernel module
1590  *          and the execution entry point for the module
1591  * Param 3: From sysinit_sub_id enumeration in /usr/include/sys/kernel.h
1592  *          Defines the module initialisation order
1593  * Param 4: From sysinit_elem_order enumeration in /usr/include/sys/kernel.h
1594  *          Defines the initialisation order of this kld relative to others
1595  *          within the same subsystem as defined by param 3
1596  */
1597 DECLARE_MODULE(siftr, siftr_mod, SI_SUB_LAST, SI_ORDER_ANY);
1598 MODULE_DEPEND(siftr, alq, 1, 1, 1);
1599 MODULE_VERSION(siftr, MODVERSION);