sys/netinet/siftr.c

   1 /*-
   2  * Copyright (c) 2007-2009
   3  *      Swinburne University of Technology, Melbourne, Australia.
   4  * Copyright (c) 2009-2010, The FreeBSD Foundation
   5  * All rights reserved.
   6  *
   7  * Portions of this software were developed at the Centre for Advanced
   8  * Internet Architectures, Swinburne University of Technology, Melbourne,
   9  * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /******************************************************
  34  * Statistical Information For TCP Research (SIFTR)
  35  *
  36  * A FreeBSD kernel module that adds very basic intrumentation to the
  37  * TCP stack, allowing internal stats to be recorded to a log file
  38  * for experimental, debugging and performance analysis purposes.
  39  *
  40  * SIFTR was first released in 2007 by James Healy and Lawrence Stewart whilst
  41  * working on the NewTCP research project at Swinburne University of
  42  * Technology's Centre for Advanced Internet Architectures, Melbourne,
  43  * Australia, which was made possible in part by a grant from the Cisco
  44  * University Research Program Fund at Community Foundation Silicon Valley.
  45  * More details are available at:
  46  *   http://caia.swin.edu.au/urp/newtcp/
  47  *
  48  * Work on SIFTR v1.2.x was sponsored by the FreeBSD Foundation as part of
  49  * the "Enhancing the FreeBSD TCP Implementation" project 2008-2009.
  50  * More details are available at:
  51  *   http://www.freebsdfoundation.org/
  52  *   http://caia.swin.edu.au/freebsd/etcp09/
  53  *
  54  * Lawrence Stewart is the current maintainer, and all contact regarding
  55  * SIFTR should be directed to him via email: lastewart@swin.edu.au
  56  *
  57  * Initial release date: June 2007
  58  * Most recent update: September 2010
  59  ******************************************************/
  60
  61 #include <sys/cdefs.h>
  62 __FBSDID("$FreeBSD$");
  63
  64 #include <sys/param.h>
  65 #include <sys/alq.h>
  66 #include <sys/errno.h>
  67 #include <sys/eventhandler.h>
  68 #include <sys/hash.h>
  69 #include <sys/kernel.h>
  70 #include <sys/kthread.h>
  71 #include <sys/lock.h>
  72 #include <sys/mbuf.h>
  73 #include <sys/module.h>
  74 #include <sys/mutex.h>
  75 #include <sys/pcpu.h>
  76 #include <sys/proc.h>
  77 #include <sys/sbuf.h>
  78 #include <sys/sdt.h>
  79 #include <sys/smp.h>
  80 #include <sys/socket.h>
  81 #include <sys/socketvar.h>
  82 #include <sys/sysctl.h>
  83 #include <sys/unistd.h>
  84
  85 #include <net/if.h>
  86 #include <net/if_var.h>
  87 #include <net/pfil.h>
  88
  89 #include <netinet/in.h>
  90 #include <netinet/in_kdtrace.h>
  91 #include <netinet/in_pcb.h>
  92 #include <netinet/in_systm.h>
  93 #include <netinet/in_var.h>
  94 #include <netinet/ip.h>
  95 #include <netinet/tcp_var.h>
  96
  97 #ifdef SIFTR_IPV6
  98 #include <netinet/ip6.h>
  99 #include <netinet6/in6_pcb.h>
 100 #endif /* SIFTR_IPV6 */
 101
 102 #include <machine/in_cksum.h>
 103
 104 /*
 105  * Three digit version number refers to X.Y.Z where:
 106  * X is the major version number
 107  * Y is bumped to mark backwards incompatible changes
 108  * Z is bumped to mark backwards compatible changes
 109  */
 110 #define V_MAJOR         1
 111 #define V_BACKBREAK     2
 112 #define V_BACKCOMPAT    4
 113 #define MODVERSION      __CONCAT(V_MAJOR, __CONCAT(V_BACKBREAK, V_BACKCOMPAT))
 114 #define MODVERSION_STR  __XSTRING(V_MAJOR) "." __XSTRING(V_BACKBREAK) "." \
 115     __XSTRING(V_BACKCOMPAT)
 116
 117 #define HOOK 0
 118 #define UNHOOK 1
 119 #define SIFTR_EXPECTED_MAX_TCP_FLOWS 65536
 120 #define SYS_NAME "FreeBSD"
 121 #define PACKET_TAG_SIFTR 100
 122 #define PACKET_COOKIE_SIFTR 21749576
 123 #define SIFTR_LOG_FILE_MODE 0644
 124 #define SIFTR_DISABLE 0
 125 #define SIFTR_ENABLE 1
 126
 127 /*
 128  * Hard upper limit on the length of log messages. Bump this up if you add new
 129  * data fields such that the line length could exceed the below value.
 130  */
 131 #define MAX_LOG_MSG_LEN 200
 132 /* XXX: Make this a sysctl tunable. */
 133 #define SIFTR_ALQ_BUFLEN (1000*MAX_LOG_MSG_LEN)
 134
 135 /*
 136  * 1 byte for IP version
 137  * IPv4: src/dst IP (4+4) + src/dst port (2+2) = 12 bytes
 138  * IPv6: src/dst IP (16+16) + src/dst port (2+2) = 36 bytes
 139  */
 140 #ifdef SIFTR_IPV6
 141 #define FLOW_KEY_LEN 37
 142 #else
 143 #define FLOW_KEY_LEN 13
 144 #endif
 145
 146 #ifdef SIFTR_IPV6
 147 #define SIFTR_IPMODE 6
 148 #else
 149 #define SIFTR_IPMODE 4
 150 #endif
 151
 152 /* useful macros */
 153 #define CAST_PTR_INT(X) (*((int*)(X)))
 154
 155 #define UPPER_SHORT(X)  (((X) & 0xFFFF0000) >> 16)
 156 #define LOWER_SHORT(X)  ((X) & 0x0000FFFF)
 157
 158 #define FIRST_OCTET(X)  (((X) & 0xFF000000) >> 24)
 159 #define SECOND_OCTET(X) (((X) & 0x00FF0000) >> 16)
 160 #define THIRD_OCTET(X)  (((X) & 0x0000FF00) >> 8)
 161 #define FOURTH_OCTET(X) ((X) & 0x000000FF)
 162
 163 static MALLOC_DEFINE(M_SIFTR, "siftr", "dynamic memory used by SIFTR");
 164 static MALLOC_DEFINE(M_SIFTR_PKTNODE, "siftr_pktnode",
 165     "SIFTR pkt_node struct");
 166 static MALLOC_DEFINE(M_SIFTR_HASHNODE, "siftr_hashnode",
 167     "SIFTR flow_hash_node struct");
 168
 169 /* Used as links in the pkt manager queue. */
 170 struct pkt_node {
 171         /* Timestamp of pkt as noted in the pfil hook. */
 172         struct timeval          tval;
 173         /* Direction pkt is travelling; either PFIL_IN or PFIL_OUT. */
 174         uint8_t                 direction;
 175         /* IP version pkt_node relates to; either INP_IPV4 or INP_IPV6. */
 176         uint8_t                 ipver;
 177         /* Hash of the pkt which triggered the log message. */
 178         uint32_t                hash;
 179         /* Local/foreign IP address. */
 180 #ifdef SIFTR_IPV6
 181         uint32_t                ip_laddr[4];
 182         uint32_t                ip_faddr[4];
 183 #else
 184         uint8_t                 ip_laddr[4];
 185         uint8_t                 ip_faddr[4];
 186 #endif
 187         /* Local TCP port. */
 188         uint16_t                tcp_localport;
 189         /* Foreign TCP port. */
 190         uint16_t                tcp_foreignport;
 191         /* Congestion Window (bytes). */
 192         u_long                  snd_cwnd;
 193         /* Sending Window (bytes). */
 194         u_long                  snd_wnd;
 195         /* Receive Window (bytes). */
 196         u_long                  rcv_wnd;
 197         /* Unused (was: Bandwidth Controlled Window (bytes)). */
 198         u_long                  snd_bwnd;
 199         /* Slow Start Threshold (bytes). */
 200         u_long                  snd_ssthresh;
 201         /* Current state of the TCP FSM. */
 202         int                     conn_state;
 203         /* Max Segment Size (bytes). */
 204         u_int                   max_seg_size;
 205         /*
 206          * Smoothed RTT stored as found in the TCP control block
 207          * in units of (TCP_RTT_SCALE*hz).
 208          */
 209         int                     smoothed_rtt;
 210         /* Is SACK enabled? */
 211         u_char                  sack_enabled;
 212         /* Window scaling for snd window. */
 213         u_char                  snd_scale;
 214         /* Window scaling for recv window. */
 215         u_char                  rcv_scale;
 216         /* TCP control block flags. */
 217         u_int                   flags;
 218         /* Retransmit timeout length. */
 219         int                     rxt_length;
 220         /* Size of the TCP send buffer in bytes. */
 221         u_int                   snd_buf_hiwater;
 222         /* Current num bytes in the send socket buffer. */
 223         u_int                   snd_buf_cc;
 224         /* Size of the TCP receive buffer in bytes. */
 225         u_int                   rcv_buf_hiwater;
 226         /* Current num bytes in the receive socket buffer. */
 227         u_int                   rcv_buf_cc;
 228         /* Number of bytes inflight that we are waiting on ACKs for. */
 229         u_int                   sent_inflight_bytes;
 230         /* Number of segments currently in the reassembly queue. */
 231         int                     t_segqlen;
 232         /* Flowid for the connection. */
 233         u_int                   flowid;
 234         /* Flow type for the connection. */
 235         u_int                   flowtype;
 236         /* Link to next pkt_node in the list. */
 237         STAILQ_ENTRY(pkt_node)  nodes;
 238 };
 239
 240 struct flow_hash_node
 241 {
 242         uint16_t counter;
 243         uint8_t key[FLOW_KEY_LEN];
 244         LIST_ENTRY(flow_hash_node) nodes;
 245 };
 246
 247 struct siftr_stats
 248 {
 249         /* # TCP pkts seen by the SIFTR PFIL hooks, including any skipped. */
 250         uint64_t n_in;
 251         uint64_t n_out;
 252         /* # pkts skipped due to failed malloc calls. */
 253         uint32_t nskip_in_malloc;
 254         uint32_t nskip_out_malloc;
 255         /* # pkts skipped due to failed mtx acquisition. */
 256         uint32_t nskip_in_mtx;
 257         uint32_t nskip_out_mtx;
 258         /* # pkts skipped due to failed inpcb lookups. */
 259         uint32_t nskip_in_inpcb;
 260         uint32_t nskip_out_inpcb;
 261         /* # pkts skipped due to failed tcpcb lookups. */
 262         uint32_t nskip_in_tcpcb;
 263         uint32_t nskip_out_tcpcb;
 264         /* # pkts skipped due to stack reinjection. */
 265         uint32_t nskip_in_dejavu;
 266         uint32_t nskip_out_dejavu;
 267 };
 268
 269 static DPCPU_DEFINE(struct siftr_stats, ss);
 270
 271 static volatile unsigned int siftr_exit_pkt_manager_thread = 0;
 272 static unsigned int siftr_enabled = 0;
 273 static unsigned int siftr_pkts_per_log = 1;
 274 static unsigned int siftr_generate_hashes = 0;
 275 /* static unsigned int siftr_binary_log = 0; */
 276 static char siftr_logfile[PATH_MAX] = "/var/log/siftr.log";
 277 static char siftr_logfile_shadow[PATH_MAX] = "/var/log/siftr.log";
 278 static u_long siftr_hashmask;
 279 STAILQ_HEAD(pkthead, pkt_node) pkt_queue = STAILQ_HEAD_INITIALIZER(pkt_queue);
 280 LIST_HEAD(listhead, flow_hash_node) *counter_hash;
 281 static int wait_for_pkt;
 282 static struct alq *siftr_alq = NULL;
 283 static struct mtx siftr_pkt_queue_mtx;
 284 static struct mtx siftr_pkt_mgr_mtx;
 285 static struct thread *siftr_pkt_manager_thr = NULL;
 286 /*
 287  * pfil.h defines PFIL_IN as 1 and PFIL_OUT as 2,
 288  * which we use as an index into this array.
 289  */
 290 static char direction[3] = {'\0', 'i','o'};
 291
 292 /* Required function prototypes. */
 293 static int siftr_sysctl_enabled_handler(SYSCTL_HANDLER_ARGS);
 294 static int siftr_sysctl_logfile_name_handler(SYSCTL_HANDLER_ARGS);
 295
 296
 297 /* Declare the net.inet.siftr sysctl tree and populate it. */
 298
 299 SYSCTL_DECL(_net_inet_siftr);
 300
 301 SYSCTL_NODE(_net_inet, OID_AUTO, siftr, CTLFLAG_RW, NULL,
 302     "siftr related settings");
 303
 304 SYSCTL_PROC(_net_inet_siftr, OID_AUTO, enabled, CTLTYPE_UINT|CTLFLAG_RW,
 305     &siftr_enabled, 0, &siftr_sysctl_enabled_handler, "IU",
 306     "switch siftr module operations on/off");
 307
 308 SYSCTL_PROC(_net_inet_siftr, OID_AUTO, logfile, CTLTYPE_STRING|CTLFLAG_RW,
 309     &siftr_logfile_shadow, sizeof(siftr_logfile_shadow), &siftr_sysctl_logfile_name_handler,
 310     "A", "file to save siftr log messages to");
 311
 312 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, ppl, CTLFLAG_RW,
 313     &siftr_pkts_per_log, 1,
 314     "number of packets between generating a log message");
 315
 316 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, genhashes, CTLFLAG_RW,
 317     &siftr_generate_hashes, 0,
 318     "enable packet hash generation");
 319
 320 /* XXX: TODO
 321 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, binary, CTLFLAG_RW,
 322     &siftr_binary_log, 0,
 323     "write log files in binary instead of ascii");
 324 */
 325
 326
 327 /* Begin functions. */
 328
 329 static void
 330 siftr_process_pkt(struct pkt_node * pkt_node)
 331 {
 332         struct flow_hash_node *hash_node;
 333         struct listhead *counter_list;
 334         struct siftr_stats *ss;
 335         struct ale *log_buf;
 336         uint8_t key[FLOW_KEY_LEN];
 337         uint8_t found_match, key_offset;
 338
 339         hash_node = NULL;
 340         ss = DPCPU_PTR(ss);
 341         found_match = 0;
 342         key_offset = 1;
 343
 344         /*
 345          * Create the key that will be used to create a hash index
 346          * into our hash table. Our key consists of:
 347          * ipversion, localip, localport, foreignip, foreignport
 348          */
 349         key[0] = pkt_node->ipver;
 350         memcpy(key + key_offset, &pkt_node->ip_laddr,
 351             sizeof(pkt_node->ip_laddr));
 352         key_offset += sizeof(pkt_node->ip_laddr);
 353         memcpy(key + key_offset, &pkt_node->tcp_localport,
 354             sizeof(pkt_node->tcp_localport));
 355         key_offset += sizeof(pkt_node->tcp_localport);
 356         memcpy(key + key_offset, &pkt_node->ip_faddr,
 357             sizeof(pkt_node->ip_faddr));
 358         key_offset += sizeof(pkt_node->ip_faddr);
 359         memcpy(key + key_offset, &pkt_node->tcp_foreignport,
 360             sizeof(pkt_node->tcp_foreignport));
 361
 362         counter_list = counter_hash +
 363             (hash32_buf(key, sizeof(key), 0) & siftr_hashmask);
 364
 365         /*
 366          * If the list is not empty i.e. the hash index has
 367          * been used by another flow previously.
 368          */
 369         if (LIST_FIRST(counter_list) != NULL) {
 370                 /*
 371                  * Loop through the hash nodes in the list.
 372                  * There should normally only be 1 hash node in the list,
 373                  * except if there have been collisions at the hash index
 374                  * computed by hash32_buf().
 375                  */
 376                 LIST_FOREACH(hash_node, counter_list, nodes) {
 377                         /*
 378                          * Check if the key for the pkt we are currently
 379                          * processing is the same as the key stored in the
 380                          * hash node we are currently processing.
 381                          * If they are the same, then we've found the
 382                          * hash node that stores the counter for the flow
 383                          * the pkt belongs to.
 384                          */
 385                         if (memcmp(hash_node->key, key, sizeof(key)) == 0) {
 386                                 found_match = 1;
 387                                 break;
 388                         }
 389                 }
 390         }
 391
 392         /* If this flow hash hasn't been seen before or we have a collision. */
 393         if (hash_node == NULL || !found_match) {
 394                 /* Create a new hash node to store the flow's counter. */
 395                 hash_node = malloc(sizeof(struct flow_hash_node),
 396                     M_SIFTR_HASHNODE, M_WAITOK);
 397
 398                 if (hash_node != NULL) {
 399                         /* Initialise our new hash node list entry. */
 400                         hash_node->counter = 0;
 401                         memcpy(hash_node->key, key, sizeof(key));
 402                         LIST_INSERT_HEAD(counter_list, hash_node, nodes);
 403                 } else {
 404                         /* Malloc failed. */
 405                         if (pkt_node->direction == PFIL_IN)
 406                                 ss->nskip_in_malloc++;
 407                         else
 408                                 ss->nskip_out_malloc++;
 409
 410                         return;
 411                 }
 412         } else if (siftr_pkts_per_log > 1) {
 413                 /*
 414                  * Taking the remainder of the counter divided
 415                  * by the current value of siftr_pkts_per_log
 416                  * and storing that in counter provides a neat
 417                  * way to modulate the frequency of log
 418                  * messages being written to the log file.
 419                  */
 420                 hash_node->counter = (hash_node->counter + 1) %
 421                     siftr_pkts_per_log;
 422
 423                 /*
 424                  * If we have not seen enough packets since the last time
 425                  * we wrote a log message for this connection, return.
 426                  */
 427                 if (hash_node->counter > 0)
 428                         return;
 429         }
 430
 431         log_buf = alq_getn(siftr_alq, MAX_LOG_MSG_LEN, ALQ_WAITOK);
 432
 433         if (log_buf == NULL)
 434                 return; /* Should only happen if the ALQ is shutting down. */
 435
 436 #ifdef SIFTR_IPV6
 437         pkt_node->ip_laddr[3] = ntohl(pkt_node->ip_laddr[3]);
 438         pkt_node->ip_faddr[3] = ntohl(pkt_node->ip_faddr[3]);
 439
 440         if (pkt_node->ipver == INP_IPV6) { /* IPv6 packet */
 441                 pkt_node->ip_laddr[0] = ntohl(pkt_node->ip_laddr[0]);
 442                 pkt_node->ip_laddr[1] = ntohl(pkt_node->ip_laddr[1]);
 443                 pkt_node->ip_laddr[2] = ntohl(pkt_node->ip_laddr[2]);
 444                 pkt_node->ip_faddr[0] = ntohl(pkt_node->ip_faddr[0]);
 445                 pkt_node->ip_faddr[1] = ntohl(pkt_node->ip_faddr[1]);
 446                 pkt_node->ip_faddr[2] = ntohl(pkt_node->ip_faddr[2]);
 447
 448                 /* Construct an IPv6 log message. */
 449                 log_buf->ae_bytesused = snprintf(log_buf->ae_data,
 450                     MAX_LOG_MSG_LEN,
 451                     "%c,0x%08x,%zd.%06ld,%x:%x:%x:%x:%x:%x:%x:%x,%u,%x:%x:%x:"
 452                     "%x:%x:%x:%x:%x,%u,%ld,%ld,%ld,%ld,%ld,%u,%u,%u,%u,%u,%u,"
 453                     "%u,%d,%u,%u,%u,%u,%u,%u,%u,%u\n",
 454                     direction[pkt_node->direction],
 455                     pkt_node->hash,
 456                     pkt_node->tval.tv_sec,
 457                     pkt_node->tval.tv_usec,
 458                     UPPER_SHORT(pkt_node->ip_laddr[0]),
 459                     LOWER_SHORT(pkt_node->ip_laddr[0]),
 460                     UPPER_SHORT(pkt_node->ip_laddr[1]),
 461                     LOWER_SHORT(pkt_node->ip_laddr[1]),
 462                     UPPER_SHORT(pkt_node->ip_laddr[2]),
 463                     LOWER_SHORT(pkt_node->ip_laddr[2]),
 464                     UPPER_SHORT(pkt_node->ip_laddr[3]),
 465                     LOWER_SHORT(pkt_node->ip_laddr[3]),
 466                     ntohs(pkt_node->tcp_localport),
 467                     UPPER_SHORT(pkt_node->ip_faddr[0]),
 468                     LOWER_SHORT(pkt_node->ip_faddr[0]),
 469                     UPPER_SHORT(pkt_node->ip_faddr[1]),
 470                     LOWER_SHORT(pkt_node->ip_faddr[1]),
 471                     UPPER_SHORT(pkt_node->ip_faddr[2]),
 472                     LOWER_SHORT(pkt_node->ip_faddr[2]),
 473                     UPPER_SHORT(pkt_node->ip_faddr[3]),
 474                     LOWER_SHORT(pkt_node->ip_faddr[3]),
 475                     ntohs(pkt_node->tcp_foreignport),
 476                     pkt_node->snd_ssthresh,
 477                     pkt_node->snd_cwnd,
 478                     pkt_node->snd_bwnd,
 479                     pkt_node->snd_wnd,
 480                     pkt_node->rcv_wnd,
 481                     pkt_node->snd_scale,
 482                     pkt_node->rcv_scale,
 483                     pkt_node->conn_state,
 484                     pkt_node->max_seg_size,
 485                     pkt_node->smoothed_rtt,
 486                     pkt_node->sack_enabled,
 487                     pkt_node->flags,
 488                     pkt_node->rxt_length,
 489                     pkt_node->snd_buf_hiwater,
 490                     pkt_node->snd_buf_cc,
 491                     pkt_node->rcv_buf_hiwater,
 492                     pkt_node->rcv_buf_cc,
 493                     pkt_node->sent_inflight_bytes,
 494                     pkt_node->t_segqlen,
 495                     pkt_node->flowid,
 496                     pkt_node->flowtype);
 497         } else { /* IPv4 packet */
 498                 pkt_node->ip_laddr[0] = FIRST_OCTET(pkt_node->ip_laddr[3]);
 499                 pkt_node->ip_laddr[1] = SECOND_OCTET(pkt_node->ip_laddr[3]);
 500                 pkt_node->ip_laddr[2] = THIRD_OCTET(pkt_node->ip_laddr[3]);
 501                 pkt_node->ip_laddr[3] = FOURTH_OCTET(pkt_node->ip_laddr[3]);
 502                 pkt_node->ip_faddr[0] = FIRST_OCTET(pkt_node->ip_faddr[3]);
 503                 pkt_node->ip_faddr[1] = SECOND_OCTET(pkt_node->ip_faddr[3]);
 504                 pkt_node->ip_faddr[2] = THIRD_OCTET(pkt_node->ip_faddr[3]);
 505                 pkt_node->ip_faddr[3] = FOURTH_OCTET(pkt_node->ip_faddr[3]);
 506 #endif /* SIFTR_IPV6 */
 507
 508                 /* Construct an IPv4 log message. */
 509                 log_buf->ae_bytesused = snprintf(log_buf->ae_data,
 510                     MAX_LOG_MSG_LEN,
 511                     "%c,0x%08x,%jd.%06ld,%u.%u.%u.%u,%u,%u.%u.%u.%u,%u,%ld,%ld,"
 512                     "%ld,%ld,%ld,%u,%u,%u,%u,%u,%u,%u,%d,%u,%u,%u,%u,%u,%u,%u,%u\n",
 513                     direction[pkt_node->direction],
 514                     pkt_node->hash,
 515                     (intmax_t)pkt_node->tval.tv_sec,
 516                     pkt_node->tval.tv_usec,
 517                     pkt_node->ip_laddr[0],
 518                     pkt_node->ip_laddr[1],
 519                     pkt_node->ip_laddr[2],
 520                     pkt_node->ip_laddr[3],
 521                     ntohs(pkt_node->tcp_localport),
 522                     pkt_node->ip_faddr[0],
 523                     pkt_node->ip_faddr[1],
 524                     pkt_node->ip_faddr[2],
 525                     pkt_node->ip_faddr[3],
 526                     ntohs(pkt_node->tcp_foreignport),
 527                     pkt_node->snd_ssthresh,
 528                     pkt_node->snd_cwnd,
 529                     pkt_node->snd_bwnd,
 530                     pkt_node->snd_wnd,
 531                     pkt_node->rcv_wnd,
 532                     pkt_node->snd_scale,
 533                     pkt_node->rcv_scale,
 534                     pkt_node->conn_state,
 535                     pkt_node->max_seg_size,
 536                     pkt_node->smoothed_rtt,
 537                     pkt_node->sack_enabled,
 538                     pkt_node->flags,
 539                     pkt_node->rxt_length,
 540                     pkt_node->snd_buf_hiwater,
 541                     pkt_node->snd_buf_cc,
 542                     pkt_node->rcv_buf_hiwater,
 543                     pkt_node->rcv_buf_cc,
 544                     pkt_node->sent_inflight_bytes,
 545                     pkt_node->t_segqlen,
 546                     pkt_node->flowid,
 547                     pkt_node->flowtype);
 548 #ifdef SIFTR_IPV6
 549         }
 550 #endif
 551
 552         alq_post_flags(siftr_alq, log_buf, 0);
 553 }
 554
 555
 556 static void
 557 siftr_pkt_manager_thread(void *arg)
 558 {
 559         STAILQ_HEAD(pkthead, pkt_node) tmp_pkt_queue =
 560             STAILQ_HEAD_INITIALIZER(tmp_pkt_queue);
 561         struct pkt_node *pkt_node, *pkt_node_temp;
 562         uint8_t draining;
 563
 564         draining = 2;
 565
 566         mtx_lock(&siftr_pkt_mgr_mtx);
 567
 568         /* draining == 0 when queue has been flushed and it's safe to exit. */
 569         while (draining) {
 570                 /*
 571                  * Sleep until we are signalled to wake because thread has
 572                  * been told to exit or until 1 tick has passed.
 573                  */
 574                 mtx_sleep(&wait_for_pkt, &siftr_pkt_mgr_mtx, PWAIT, "pktwait",
 575                     1);
 576
 577                 /* Gain exclusive access to the pkt_node queue. */
 578                 mtx_lock(&siftr_pkt_queue_mtx);
 579
 580                 /*
 581                  * Move pkt_queue to tmp_pkt_queue, which leaves
 582                  * pkt_queue empty and ready to receive more pkt_nodes.
 583                  */
 584                 STAILQ_CONCAT(&tmp_pkt_queue, &pkt_queue);
 585
 586                 /*
 587                  * We've finished making changes to the list. Unlock it
 588                  * so the pfil hooks can continue queuing pkt_nodes.
 589                  */
 590                 mtx_unlock(&siftr_pkt_queue_mtx);
 591
 592                 /*
 593                  * We can't hold a mutex whilst calling siftr_process_pkt
 594                  * because ALQ might sleep waiting for buffer space.
 595                  */
 596                 mtx_unlock(&siftr_pkt_mgr_mtx);
 597
 598                 /* Flush all pkt_nodes to the log file. */
 599                 STAILQ_FOREACH_SAFE(pkt_node, &tmp_pkt_queue, nodes,
 600                     pkt_node_temp) {
 601                         siftr_process_pkt(pkt_node);
 602                         STAILQ_REMOVE_HEAD(&tmp_pkt_queue, nodes);
 603                         free(pkt_node, M_SIFTR_PKTNODE);
 604                 }
 605
 606                 KASSERT(STAILQ_EMPTY(&tmp_pkt_queue),
 607                     ("SIFTR tmp_pkt_queue not empty after flush"));
 608
 609                 mtx_lock(&siftr_pkt_mgr_mtx);
 610
 611                 /*
 612                  * If siftr_exit_pkt_manager_thread gets set during the window
 613                  * where we are draining the tmp_pkt_queue above, there might
 614                  * still be pkts in pkt_queue that need to be drained.
 615                  * Allow one further iteration to occur after
 616                  * siftr_exit_pkt_manager_thread has been set to ensure
 617                  * pkt_queue is completely empty before we kill the thread.
 618                  *
 619                  * siftr_exit_pkt_manager_thread is set only after the pfil
 620                  * hooks have been removed, so only 1 extra iteration
 621                  * is needed to drain the queue.
 622                  */
 623                 if (siftr_exit_pkt_manager_thread)
 624                         draining--;
 625         }
 626
 627         mtx_unlock(&siftr_pkt_mgr_mtx);
 628
 629         /* Calls wakeup on this thread's struct thread ptr. */
 630         kthread_exit();
 631 }
 632
 633
 634 static uint32_t
 635 hash_pkt(struct mbuf *m, uint32_t offset)
 636 {
 637         uint32_t hash;
 638
 639         hash = 0;
 640
 641         while (m != NULL && offset > m->m_len) {
 642                 /*
 643                  * The IP packet payload does not start in this mbuf, so
 644                  * need to figure out which mbuf it starts in and what offset
 645                  * into the mbuf's data region the payload starts at.
 646                  */
 647                 offset -= m->m_len;
 648                 m = m->m_next;
 649         }
 650
 651         while (m != NULL) {
 652                 /* Ensure there is data in the mbuf */
 653                 if ((m->m_len - offset) > 0)
 654                         hash = hash32_buf(m->m_data + offset,
 655                             m->m_len - offset, hash);
 656
 657                 m = m->m_next;
 658                 offset = 0;
 659         }
 660
 661         return (hash);
 662 }
 663
 664
 665 /*
 666  * Check if a given mbuf has the SIFTR mbuf tag. If it does, log the fact that
 667  * it's a reinjected packet and return. If it doesn't, tag the mbuf and return.
 668  * Return value >0 means the caller should skip processing this mbuf.
 669  */
 670 static inline int
 671 siftr_chkreinject(struct mbuf *m, int dir, struct siftr_stats *ss)
 672 {
 673         if (m_tag_locate(m, PACKET_COOKIE_SIFTR, PACKET_TAG_SIFTR, NULL)
 674             != NULL) {
 675                 if (dir == PFIL_IN)
 676                         ss->nskip_in_dejavu++;
 677                 else
 678                         ss->nskip_out_dejavu++;
 679
 680                 return (1);
 681         } else {
 682                 struct m_tag *tag = m_tag_alloc(PACKET_COOKIE_SIFTR,
 683                     PACKET_TAG_SIFTR, 0, M_NOWAIT);
 684                 if (tag == NULL) {
 685                         if (dir == PFIL_IN)
 686                                 ss->nskip_in_malloc++;
 687                         else
 688                                 ss->nskip_out_malloc++;
 689
 690                         return (1);
 691                 }
 692
 693                 m_tag_prepend(m, tag);
 694         }
 695
 696         return (0);
 697 }
 698
 699
 700 /*
 701  * Look up an inpcb for a packet. Return the inpcb pointer if found, or NULL
 702  * otherwise.
 703  */
 704 static inline struct inpcb *
 705 siftr_findinpcb(int ipver, struct ip *ip, struct mbuf *m, uint16_t sport,
 706     uint16_t dport, int dir, struct siftr_stats *ss)
 707 {
 708         struct inpcb *inp;
 709
 710         /* We need the tcbinfo lock. */
 711         INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
 712
 713         if (dir == PFIL_IN)
 714                 inp = (ipver == INP_IPV4 ?
 715                     in_pcblookup(&V_tcbinfo, ip->ip_src, sport, ip->ip_dst,
 716                     dport, INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif)
 717                     :
 718 #ifdef SIFTR_IPV6
 719                     in6_pcblookup(&V_tcbinfo,
 720                     &((struct ip6_hdr *)ip)->ip6_src, sport,
 721                     &((struct ip6_hdr *)ip)->ip6_dst, dport, INPLOOKUP_RLOCKPCB,
 722                     m->m_pkthdr.rcvif)
 723 #else
 724                     NULL
 725 #endif
 726                     );
 727
 728         else
 729                 inp = (ipver == INP_IPV4 ?
 730                     in_pcblookup(&V_tcbinfo, ip->ip_dst, dport, ip->ip_src,
 731                     sport, INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif)
 732                     :
 733 #ifdef SIFTR_IPV6
 734                     in6_pcblookup(&V_tcbinfo,
 735                     &((struct ip6_hdr *)ip)->ip6_dst, dport,
 736                     &((struct ip6_hdr *)ip)->ip6_src, sport, INPLOOKUP_RLOCKPCB,
 737                     m->m_pkthdr.rcvif)
 738 #else
 739                     NULL
 740 #endif
 741                     );
 742
 743         /* If we can't find the inpcb, bail. */
 744         if (inp == NULL) {
 745                 if (dir == PFIL_IN)
 746                         ss->nskip_in_inpcb++;
 747                 else
 748                         ss->nskip_out_inpcb++;
 749         }
 750
 751         return (inp);
 752 }
 753
 754
 755 static inline void
 756 siftr_siftdata(struct pkt_node *pn, struct inpcb *inp, struct tcpcb *tp,
 757     int ipver, int dir, int inp_locally_locked)
 758 {
 759 #ifdef SIFTR_IPV6
 760         if (ipver == INP_IPV4) {
 761                 pn->ip_laddr[3] = inp->inp_laddr.s_addr;
 762                 pn->ip_faddr[3] = inp->inp_faddr.s_addr;
 763 #else
 764                 *((uint32_t *)pn->ip_laddr) = inp->inp_laddr.s_addr;
 765                 *((uint32_t *)pn->ip_faddr) = inp->inp_faddr.s_addr;
 766 #endif
 767 #ifdef SIFTR_IPV6
 768         } else {
 769                 pn->ip_laddr[0] = inp->in6p_laddr.s6_addr32[0];
 770                 pn->ip_laddr[1] = inp->in6p_laddr.s6_addr32[1];
 771                 pn->ip_laddr[2] = inp->in6p_laddr.s6_addr32[2];
 772                 pn->ip_laddr[3] = inp->in6p_laddr.s6_addr32[3];
 773                 pn->ip_faddr[0] = inp->in6p_faddr.s6_addr32[0];
 774                 pn->ip_faddr[1] = inp->in6p_faddr.s6_addr32[1];
 775                 pn->ip_faddr[2] = inp->in6p_faddr.s6_addr32[2];
 776                 pn->ip_faddr[3] = inp->in6p_faddr.s6_addr32[3];
 777         }
 778 #endif
 779         pn->tcp_localport = inp->inp_lport;
 780         pn->tcp_foreignport = inp->inp_fport;
 781         pn->snd_cwnd = tp->snd_cwnd;
 782         pn->snd_wnd = tp->snd_wnd;
 783         pn->rcv_wnd = tp->rcv_wnd;
 784         pn->snd_bwnd = 0;               /* Unused, kept for compat. */
 785         pn->snd_ssthresh = tp->snd_ssthresh;
 786         pn->snd_scale = tp->snd_scale;
 787         pn->rcv_scale = tp->rcv_scale;
 788         pn->conn_state = tp->t_state;
 789         pn->max_seg_size = tp->t_maxseg;
 790         pn->smoothed_rtt = tp->t_srtt;
 791         pn->sack_enabled = (tp->t_flags & TF_SACK_PERMIT) != 0;
 792         pn->flags = tp->t_flags;
 793         pn->rxt_length = tp->t_rxtcur;
 794         pn->snd_buf_hiwater = inp->inp_socket->so_snd.sb_hiwat;
 795         pn->snd_buf_cc = sbused(&inp->inp_socket->so_snd);
 796         pn->rcv_buf_hiwater = inp->inp_socket->so_rcv.sb_hiwat;
 797         pn->rcv_buf_cc = sbused(&inp->inp_socket->so_rcv);
 798         pn->sent_inflight_bytes = tp->snd_max - tp->snd_una;
 799         pn->t_segqlen = tp->t_segqlen;
 800         pn->flowid = inp->inp_flowid;
 801         pn->flowtype = inp->inp_flowtype;
 802
 803         /* We've finished accessing the tcb so release the lock. */
 804         if (inp_locally_locked)
 805                 INP_RUNLOCK(inp);
 806
 807         pn->ipver = ipver;
 808         pn->direction = dir;
 809
 810         /*
 811          * Significantly more accurate than using getmicrotime(), but slower!
 812          * Gives true microsecond resolution at the expense of a hit to
 813          * maximum pps throughput processing when SIFTR is loaded and enabled.
 814          */
 815         microtime(&pn->tval);
 816         TCP_PROBE1(siftr, &pn);
 817
 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 int
 830 siftr_chkpkt(void *arg, struct mbuf **m, struct ifnet *ifp, int dir,
 831     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;
 840
 841         inp_locally_locked = 0;
 842         ss = DPCPU_PTR(ss);
 843
 844         /*
 845          * m_pullup is not required here because ip_{input|output}
 846          * already do the heavy lifting for us.
 847          */
 848
 849         ip = mtod(*m, struct ip *);
 850
 851         /* Only continue processing if the packet is TCP. */
 852         if (ip->ip_p != IPPROTO_TCP)
 853                 goto ret;
 854
 855         /*
 856          * If a kernel subsystem reinjects packets into the stack, our pfil
 857          * hook will be called multiple times for the same packet.
 858          * Make sure we only process unique packets.
 859          */
 860         if (siftr_chkreinject(*m, dir, ss))
 861                 goto ret;
 862
 863         if (dir == PFIL_IN)
 864                 ss->n_in++;
 865         else
 866                 ss->n_out++;
 867
 868         /*
 869          * Create a tcphdr struct starting at the correct offset
 870          * in the IP packet. ip->ip_hl gives the ip header length
 871          * in 4-byte words, so multiply it to get the size in bytes.
 872          */
 873         ip_hl = (ip->ip_hl << 2);
 874         th = (struct tcphdr *)((caddr_t)ip + ip_hl);
 875
 876         /*
 877          * If the pfil hooks don't provide a pointer to the
 878          * inpcb, we need to find it ourselves and lock it.
 879          */
 880         if (!inp) {
 881                 /* Find the corresponding inpcb for this pkt. */
 882                 inp = siftr_findinpcb(INP_IPV4, ip, *m, th->th_sport,
 883                     th->th_dport, dir, ss);
 884
 885                 if (inp == NULL)
 886                         goto ret;
 887                 else
 888                         inp_locally_locked = 1;
 889         }
 890
 891         INP_LOCK_ASSERT(inp);
 892
 893         /* Find the TCP control block that corresponds with this packet */
 894         tp = intotcpcb(inp);
 895
 896         /*
 897          * If we can't find the TCP control block (happens occasionaly for a
 898          * packet sent during the shutdown phase of a TCP connection),
 899          * or we're in the timewait state, bail
 900          */
 901         if (tp == NULL || inp->inp_flags & INP_TIMEWAIT) {
 902                 if (dir == PFIL_IN)
 903                         ss->nskip_in_tcpcb++;
 904                 else
 905                         ss->nskip_out_tcpcb++;
 906
 907                 goto inp_unlock;
 908         }
 909
 910         pn = malloc(sizeof(struct pkt_node), M_SIFTR_PKTNODE, M_NOWAIT|M_ZERO);
 911
 912         if (pn == NULL) {
 913                 if (dir == PFIL_IN)
 914                         ss->nskip_in_malloc++;
 915                 else
 916                         ss->nskip_out_malloc++;
 917
 918                 goto inp_unlock;
 919         }
 920
 921         siftr_siftdata(pn, inp, tp, INP_IPV4, dir, inp_locally_locked);
 922
 923         if (siftr_generate_hashes) {
 924                 if ((*m)->m_pkthdr.csum_flags & CSUM_TCP) {
 925                         /*
 926                          * For outbound packets, the TCP checksum isn't
 927                          * calculated yet. This is a problem for our packet
 928                          * hashing as the receiver will calc a different hash
 929                          * to ours if we don't include the correct TCP checksum
 930                          * in the bytes being hashed. To work around this
 931                          * problem, we manually calc the TCP checksum here in
 932                          * software. We unset the CSUM_TCP flag so the lower
 933                          * layers don't recalc it.
 934                          */
 935                         (*m)->m_pkthdr.csum_flags &= ~CSUM_TCP;
 936
 937                         /*
 938                          * Calculate the TCP checksum in software and assign
 939                          * to correct TCP header field, which will follow the
 940                          * packet mbuf down the stack. The trick here is that
 941                          * tcp_output() sets th->th_sum to the checksum of the
 942                          * pseudo header for us already. Because of the nature
 943                          * of the checksumming algorithm, we can sum over the
 944                          * entire IP payload (i.e. TCP header and data), which
 945                          * will include the already calculated pseduo header
 946                          * checksum, thus giving us the complete TCP checksum.
 947                          *
 948                          * To put it in simple terms, if checksum(1,2,3,4)=10,
 949                          * then checksum(1,2,3,4,5) == checksum(10,5).
 950                          * This property is what allows us to "cheat" and
 951                          * checksum only the IP payload which has the TCP
 952                          * th_sum field populated with the pseudo header's
 953                          * checksum, and not need to futz around checksumming
 954                          * pseudo header bytes and TCP header/data in one hit.
 955                          * Refer to RFC 1071 for more info.
 956                          *
 957                          * NB: in_cksum_skip(struct mbuf *m, int len, int skip)
 958                          * in_cksum_skip 2nd argument is NOT the number of
 959                          * bytes to read from the mbuf at "skip" bytes offset
 960                          * from the start of the mbuf (very counter intuitive!).
 961                          * The number of bytes to read is calculated internally
 962                          * by the function as len-skip i.e. to sum over the IP
 963                          * payload (TCP header + data) bytes, it is INCORRECT
 964                          * to call the function like this:
 965                          * in_cksum_skip(at, ip->ip_len - offset, offset)
 966                          * Rather, it should be called like this:
 967                          * in_cksum_skip(at, ip->ip_len, offset)
 968                          * which means read "ip->ip_len - offset" bytes from
 969                          * the mbuf cluster "at" at offset "offset" bytes from
 970                          * the beginning of the "at" mbuf's data pointer.
 971                          */
 972                         th->th_sum = in_cksum_skip(*m, ntohs(ip->ip_len),
 973                             ip_hl);
 974                 }
 975
 976                 /*
 977                  * XXX: Having to calculate the checksum in software and then
 978                  * hash over all bytes is really inefficient. Would be nice to
 979                  * find a way to create the hash and checksum in the same pass
 980                  * over the bytes.
 981                  */
 982                 pn->hash = hash_pkt(*m, ip_hl);
 983         }
 984
 985         mtx_lock(&siftr_pkt_queue_mtx);
 986         STAILQ_INSERT_TAIL(&pkt_queue, pn, nodes);
 987         mtx_unlock(&siftr_pkt_queue_mtx);
 988         goto ret;
 989
 990 inp_unlock:
 991         if (inp_locally_locked)
 992                 INP_RUNLOCK(inp);
 993
 994 ret:
 995         /* Returning 0 ensures pfil will not discard the pkt */
 996         return (0);
 997 }
 998
 999
1000 #ifdef SIFTR_IPV6
1001 static int
1002 siftr_chkpkt6(void *arg, struct mbuf **m, struct ifnet *ifp, int dir,
1003     struct inpcb *inp)
1004 {
1005         struct pkt_node *pn;
1006         struct ip6_hdr *ip6;
1007         struct tcphdr *th;
1008         struct tcpcb *tp;
1009         struct siftr_stats *ss;
1010         unsigned int ip6_hl;
1011         int inp_locally_locked;
1012
1013         inp_locally_locked = 0;
1014         ss = DPCPU_PTR(ss);
1015
1016         /*
1017          * m_pullup is not required here because ip6_{input|output}
1018          * already do the heavy lifting for us.
1019          */
1020
1021         ip6 = mtod(*m, struct ip6_hdr *);
1022
1023         /*
1024          * Only continue processing if the packet is TCP
1025          * XXX: We should follow the next header fields
1026          * as shown on Pg 6 RFC 2460, but right now we'll
1027          * only check pkts that have no extension headers.
1028          */
1029         if (ip6->ip6_nxt != IPPROTO_TCP)
1030                 goto ret6;
1031
1032         /*
1033          * If a kernel subsystem reinjects packets into the stack, our pfil
1034          * hook will be called multiple times for the same packet.
1035          * Make sure we only process unique packets.
1036          */
1037         if (siftr_chkreinject(*m, dir, ss))
1038                 goto ret6;
1039
1040         if (dir == PFIL_IN)
1041                 ss->n_in++;
1042         else
1043                 ss->n_out++;
1044
1045         ip6_hl = sizeof(struct ip6_hdr);
1046
1047         /*
1048          * Create a tcphdr struct starting at the correct offset
1049          * in the ipv6 packet. ip->ip_hl gives the ip header length
1050          * in 4-byte words, so multiply it to get the size in bytes.
1051          */
1052         th = (struct tcphdr *)((caddr_t)ip6 + ip6_hl);
1053
1054         /*
1055          * For inbound packets, the pfil hooks don't provide a pointer to the
1056          * inpcb, so we need to find it ourselves and lock it.
1057          */
1058         if (!inp) {
1059                 /* Find the corresponding inpcb for this pkt. */
1060                 inp = siftr_findinpcb(INP_IPV6, (struct ip *)ip6, *m,
1061                     th->th_sport, th->th_dport, dir, ss);
1062
1063                 if (inp == NULL)
1064                         goto ret6;
1065                 else
1066                         inp_locally_locked = 1;
1067         }
1068
1069         /* Find the TCP control block that corresponds with this packet. */
1070         tp = intotcpcb(inp);
1071
1072         /*
1073          * If we can't find the TCP control block (happens occasionaly for a
1074          * packet sent during the shutdown phase of a TCP connection),
1075          * or we're in the timewait state, bail.
1076          */
1077         if (tp == NULL || inp->inp_flags & INP_TIMEWAIT) {
1078                 if (dir == PFIL_IN)
1079                         ss->nskip_in_tcpcb++;
1080                 else
1081                         ss->nskip_out_tcpcb++;
1082
1083                 goto inp_unlock6;
1084         }
1085
1086         pn = malloc(sizeof(struct pkt_node), M_SIFTR_PKTNODE, M_NOWAIT|M_ZERO);
1087
1088         if (pn == NULL) {
1089                 if (dir == PFIL_IN)
1090                         ss->nskip_in_malloc++;
1091                 else
1092                         ss->nskip_out_malloc++;
1093
1094                 goto inp_unlock6;
1095         }
1096
1097         siftr_siftdata(pn, inp, tp, INP_IPV6, dir, inp_locally_locked);
1098
1099         /* XXX: Figure out how to generate hashes for IPv6 packets. */
1100
1101         mtx_lock(&siftr_pkt_queue_mtx);
1102         STAILQ_INSERT_TAIL(&pkt_queue, pn, nodes);
1103         mtx_unlock(&siftr_pkt_queue_mtx);
1104         goto ret6;
1105
1106 inp_unlock6:
1107         if (inp_locally_locked)
1108                 INP_RUNLOCK(inp);
1109
1110 ret6:
1111         /* Returning 0 ensures pfil will not discard the pkt. */
1112         return (0);
1113 }
1114 #endif /* #ifdef SIFTR_IPV6 */
1115
1116
1117 static int
1118 siftr_pfil(int action)
1119 {
1120         struct pfil_head *pfh_inet;
1121 #ifdef SIFTR_IPV6
1122         struct pfil_head *pfh_inet6;
1123 #endif
1124         VNET_ITERATOR_DECL(vnet_iter);
1125
1126         VNET_LIST_RLOCK();
1127         VNET_FOREACH(vnet_iter) {
1128                 CURVNET_SET(vnet_iter);
1129                 pfh_inet = pfil_head_get(PFIL_TYPE_AF, AF_INET);
1130 #ifdef SIFTR_IPV6
1131                 pfh_inet6 = pfil_head_get(PFIL_TYPE_AF, AF_INET6);
1132 #endif
1133
1134                 if (action == HOOK) {
1135                         pfil_add_hook(siftr_chkpkt, NULL,
1136                             PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh_inet);
1137 #ifdef SIFTR_IPV6
1138                         pfil_add_hook(siftr_chkpkt6, NULL,
1139                             PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh_inet6);
1140 #endif
1141                 } else if (action == UNHOOK) {
1142                         pfil_remove_hook(siftr_chkpkt, NULL,
1143                             PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh_inet);
1144 #ifdef SIFTR_IPV6
1145                         pfil_remove_hook(siftr_chkpkt6, NULL,
1146                             PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh_inet6);
1147 #endif
1148                 }
1149                 CURVNET_RESTORE();
1150         }
1151         VNET_LIST_RUNLOCK();
1152
1153         return (0);
1154 }
1155
1156
1157 static int
1158 siftr_sysctl_logfile_name_handler(SYSCTL_HANDLER_ARGS)
1159 {
1160         struct alq *new_alq;
1161         int error;
1162
1163         error = sysctl_handle_string(oidp, arg1, arg2, req);
1164
1165         /* Check for error or same filename */
1166         if (error != 0 || req->newptr == NULL ||
1167             strncmp(siftr_logfile, arg1, arg2) == 0)
1168                 goto done;
1169
1170         /* Filname changed */
1171         error = alq_open(&new_alq, arg1, curthread->td_ucred,
1172             SIFTR_LOG_FILE_MODE, SIFTR_ALQ_BUFLEN, 0);
1173         if (error != 0)
1174                 goto done;
1175
1176         /*
1177          * If disabled, siftr_alq == NULL so we simply close
1178          * the alq as we've proved it can be opened.
1179          * If enabled, close the existing alq and switch the old
1180          * for the new.
1181          */
1182         if (siftr_alq == NULL) {
1183                 alq_close(new_alq);
1184         } else {
1185                 alq_close(siftr_alq);
1186                 siftr_alq = new_alq;
1187         }
1188
1189         /* Update filename upon success */
1190         strlcpy(siftr_logfile, arg1, arg2);
1191 done:
1192         return (error);
1193 }
1194
1195 static int
1196 siftr_manage_ops(uint8_t action)
1197 {
1198         struct siftr_stats totalss;
1199         struct timeval tval;
1200         struct flow_hash_node *counter, *tmp_counter;
1201         struct sbuf *s;
1202         int i, key_index, ret, error;
1203         uint32_t bytes_to_write, total_skipped_pkts;
1204         uint16_t lport, fport;
1205         uint8_t *key, ipver;
1206
1207 #ifdef SIFTR_IPV6
1208         uint32_t laddr[4];
1209         uint32_t faddr[4];
1210 #else
1211         uint8_t laddr[4];
1212         uint8_t faddr[4];
1213 #endif
1214
1215         error = 0;
1216         total_skipped_pkts = 0;
1217
1218         /* Init an autosizing sbuf that initially holds 200 chars. */
1219         if ((s = sbuf_new(NULL, NULL, 200, SBUF_AUTOEXTEND)) == NULL)
1220                 return (-1);
1221
1222         if (action == SIFTR_ENABLE) {
1223                 /*
1224                  * Create our alq
1225                  * XXX: We should abort if alq_open fails!
1226                  */
1227                 alq_open(&siftr_alq, siftr_logfile, curthread->td_ucred,
1228                     SIFTR_LOG_FILE_MODE, SIFTR_ALQ_BUFLEN, 0);
1229
1230                 STAILQ_INIT(&pkt_queue);
1231
1232                 DPCPU_ZERO(ss);
1233
1234                 siftr_exit_pkt_manager_thread = 0;
1235
1236                 ret = kthread_add(&siftr_pkt_manager_thread, NULL, NULL,
1237                     &siftr_pkt_manager_thr, RFNOWAIT, 0,
1238                     "siftr_pkt_manager_thr");
1239
1240                 siftr_pfil(HOOK);
1241
1242                 microtime(&tval);
1243
1244                 sbuf_printf(s,
1245                     "enable_time_secs=%jd\tenable_time_usecs=%06ld\t"
1246                     "siftrver=%s\thz=%u\ttcp_rtt_scale=%u\tsysname=%s\t"
1247                     "sysver=%u\tipmode=%u\n",
1248                     (intmax_t)tval.tv_sec, tval.tv_usec, MODVERSION_STR, hz,
1249                     TCP_RTT_SCALE, SYS_NAME, __FreeBSD_version, SIFTR_IPMODE);
1250
1251                 sbuf_finish(s);
1252                 alq_writen(siftr_alq, sbuf_data(s), sbuf_len(s), ALQ_WAITOK);
1253
1254         } else if (action == SIFTR_DISABLE && siftr_pkt_manager_thr != NULL) {
1255                 /*
1256                  * Remove the pfil hook functions. All threads currently in
1257                  * the hook functions are allowed to exit before siftr_pfil()
1258                  * returns.
1259                  */
1260                 siftr_pfil(UNHOOK);
1261
1262                 /* This will block until the pkt manager thread unlocks it. */
1263                 mtx_lock(&siftr_pkt_mgr_mtx);
1264
1265                 /* Tell the pkt manager thread that it should exit now. */
1266                 siftr_exit_pkt_manager_thread = 1;
1267
1268                 /*
1269                  * Wake the pkt_manager thread so it realises that
1270                  * siftr_exit_pkt_manager_thread == 1 and exits gracefully.
1271                  * The wakeup won't be delivered until we unlock
1272                  * siftr_pkt_mgr_mtx so this isn't racy.
1273                  */
1274                 wakeup(&wait_for_pkt);
1275
1276                 /* Wait for the pkt_manager thread to exit. */
1277                 mtx_sleep(siftr_pkt_manager_thr, &siftr_pkt_mgr_mtx, PWAIT,
1278                     "thrwait", 0);
1279
1280                 siftr_pkt_manager_thr = NULL;
1281                 mtx_unlock(&siftr_pkt_mgr_mtx);
1282
1283                 totalss.n_in = DPCPU_VARSUM(ss, n_in);
1284                 totalss.n_out = DPCPU_VARSUM(ss, n_out);
1285                 totalss.nskip_in_malloc = DPCPU_VARSUM(ss, nskip_in_malloc);
1286                 totalss.nskip_out_malloc = DPCPU_VARSUM(ss, nskip_out_malloc);
1287                 totalss.nskip_in_mtx = DPCPU_VARSUM(ss, nskip_in_mtx);
1288                 totalss.nskip_out_mtx = DPCPU_VARSUM(ss, nskip_out_mtx);
1289                 totalss.nskip_in_tcpcb = DPCPU_VARSUM(ss, nskip_in_tcpcb);
1290                 totalss.nskip_out_tcpcb = DPCPU_VARSUM(ss, nskip_out_tcpcb);
1291                 totalss.nskip_in_inpcb = DPCPU_VARSUM(ss, nskip_in_inpcb);
1292                 totalss.nskip_out_inpcb = DPCPU_VARSUM(ss, nskip_out_inpcb);
1293
1294                 total_skipped_pkts = totalss.nskip_in_malloc +
1295                     totalss.nskip_out_malloc + totalss.nskip_in_mtx +
1296                     totalss.nskip_out_mtx + totalss.nskip_in_tcpcb +
1297                     totalss.nskip_out_tcpcb + totalss.nskip_in_inpcb +
1298                     totalss.nskip_out_inpcb;
1299
1300                 microtime(&tval);
1301
1302                 sbuf_printf(s,
1303                     "disable_time_secs=%jd\tdisable_time_usecs=%06ld\t"
1304                     "num_inbound_tcp_pkts=%ju\tnum_outbound_tcp_pkts=%ju\t"
1305                     "total_tcp_pkts=%ju\tnum_inbound_skipped_pkts_malloc=%u\t"
1306                     "num_outbound_skipped_pkts_malloc=%u\t"
1307                     "num_inbound_skipped_pkts_mtx=%u\t"
1308                     "num_outbound_skipped_pkts_mtx=%u\t"
1309                     "num_inbound_skipped_pkts_tcpcb=%u\t"
1310                     "num_outbound_skipped_pkts_tcpcb=%u\t"
1311                     "num_inbound_skipped_pkts_inpcb=%u\t"
1312                     "num_outbound_skipped_pkts_inpcb=%u\t"
1313                     "total_skipped_tcp_pkts=%u\tflow_list=",
1314                     (intmax_t)tval.tv_sec,
1315                     tval.tv_usec,
1316                     (uintmax_t)totalss.n_in,
1317                     (uintmax_t)totalss.n_out,
1318                     (uintmax_t)(totalss.n_in + totalss.n_out),
1319                     totalss.nskip_in_malloc,
1320                     totalss.nskip_out_malloc,
1321                     totalss.nskip_in_mtx,
1322                     totalss.nskip_out_mtx,
1323                     totalss.nskip_in_tcpcb,
1324                     totalss.nskip_out_tcpcb,
1325                     totalss.nskip_in_inpcb,
1326                     totalss.nskip_out_inpcb,
1327                     total_skipped_pkts);
1328
1329                 /*
1330                  * Iterate over the flow hash, printing a summary of each
1331                  * flow seen and freeing any malloc'd memory.
1332                  * The hash consists of an array of LISTs (man 3 queue).
1333                  */
1334                 for (i = 0; i <= siftr_hashmask; i++) {
1335                         LIST_FOREACH_SAFE(counter, counter_hash + i, nodes,
1336                             tmp_counter) {
1337                                 key = counter->key;
1338                                 key_index = 1;
1339
1340                                 ipver = key[0];
1341
1342                                 memcpy(laddr, key + key_index, sizeof(laddr));
1343                                 key_index += sizeof(laddr);
1344                                 memcpy(&lport, key + key_index, sizeof(lport));
1345                                 key_index += sizeof(lport);
1346                                 memcpy(faddr, key + key_index, sizeof(faddr));
1347                                 key_index += sizeof(faddr);
1348                                 memcpy(&fport, key + key_index, sizeof(fport));
1349
1350 #ifdef SIFTR_IPV6
1351                                 laddr[3] = ntohl(laddr[3]);
1352                                 faddr[3] = ntohl(faddr[3]);
1353
1354                                 if (ipver == INP_IPV6) {
1355                                         laddr[0] = ntohl(laddr[0]);
1356                                         laddr[1] = ntohl(laddr[1]);
1357                                         laddr[2] = ntohl(laddr[2]);
1358                                         faddr[0] = ntohl(faddr[0]);
1359                                         faddr[1] = ntohl(faddr[1]);
1360                                         faddr[2] = ntohl(faddr[2]);
1361
1362                                         sbuf_printf(s,
1363                                             "%x:%x:%x:%x:%x:%x:%x:%x;%u-"
1364                                             "%x:%x:%x:%x:%x:%x:%x:%x;%u,",
1365                                             UPPER_SHORT(laddr[0]),
1366                                             LOWER_SHORT(laddr[0]),
1367                                             UPPER_SHORT(laddr[1]),
1368                                             LOWER_SHORT(laddr[1]),
1369                                             UPPER_SHORT(laddr[2]),
1370                                             LOWER_SHORT(laddr[2]),
1371                                             UPPER_SHORT(laddr[3]),
1372                                             LOWER_SHORT(laddr[3]),
1373                                             ntohs(lport),
1374                                             UPPER_SHORT(faddr[0]),
1375                                             LOWER_SHORT(faddr[0]),
1376                                             UPPER_SHORT(faddr[1]),
1377                                             LOWER_SHORT(faddr[1]),
1378                                             UPPER_SHORT(faddr[2]),
1379                                             LOWER_SHORT(faddr[2]),
1380                                             UPPER_SHORT(faddr[3]),
1381                                             LOWER_SHORT(faddr[3]),
1382                                             ntohs(fport));
1383                                 } else {
1384                                         laddr[0] = FIRST_OCTET(laddr[3]);
1385                                         laddr[1] = SECOND_OCTET(laddr[3]);
1386                                         laddr[2] = THIRD_OCTET(laddr[3]);
1387                                         laddr[3] = FOURTH_OCTET(laddr[3]);
1388                                         faddr[0] = FIRST_OCTET(faddr[3]);
1389                                         faddr[1] = SECOND_OCTET(faddr[3]);
1390                                         faddr[2] = THIRD_OCTET(faddr[3]);
1391                                         faddr[3] = FOURTH_OCTET(faddr[3]);
1392 #endif
1393                                         sbuf_printf(s,
1394                                             "%u.%u.%u.%u;%u-%u.%u.%u.%u;%u,",
1395                                             laddr[0],
1396                                             laddr[1],
1397                                             laddr[2],
1398                                             laddr[3],
1399                                             ntohs(lport),
1400                                             faddr[0],
1401                                             faddr[1],
1402                                             faddr[2],
1403                                             faddr[3],
1404                                             ntohs(fport));
1405 #ifdef SIFTR_IPV6
1406                                 }
1407 #endif
1408
1409                                 free(counter, M_SIFTR_HASHNODE);
1410                         }
1411
1412                         LIST_INIT(counter_hash + i);
1413                 }
1414
1415                 sbuf_printf(s, "\n");
1416                 sbuf_finish(s);
1417
1418                 i = 0;
1419                 do {
1420                         bytes_to_write = min(SIFTR_ALQ_BUFLEN, sbuf_len(s)-i);
1421                         alq_writen(siftr_alq, sbuf_data(s)+i, bytes_to_write, ALQ_WAITOK);
1422                         i += bytes_to_write;
1423                 } while (i < sbuf_len(s));
1424
1425                 alq_close(siftr_alq);
1426                 siftr_alq = NULL;
1427         }
1428
1429         sbuf_delete(s);
1430
1431         /*
1432          * XXX: Should be using ret to check if any functions fail
1433          * and set error appropriately
1434          */
1435
1436         return (error);
1437 }
1438
1439
1440 static int
1441 siftr_sysctl_enabled_handler(SYSCTL_HANDLER_ARGS)
1442 {
1443         if (req->newptr == NULL)
1444                 goto skip;
1445
1446         /* If the value passed in isn't 0 or 1, return an error. */
1447         if (CAST_PTR_INT(req->newptr) != 0 && CAST_PTR_INT(req->newptr) != 1)
1448                 return (1);
1449
1450         /* If we are changing state (0 to 1 or 1 to 0). */
1451         if (CAST_PTR_INT(req->newptr) != siftr_enabled )
1452                 if (siftr_manage_ops(CAST_PTR_INT(req->newptr))) {
1453                         siftr_manage_ops(SIFTR_DISABLE);
1454                         return (1);
1455                 }
1456
1457 skip:
1458         return (sysctl_handle_int(oidp, arg1, arg2, req));
1459 }
1460
1461
1462 static void
1463 siftr_shutdown_handler(void *arg)
1464 {
1465         siftr_manage_ops(SIFTR_DISABLE);
1466 }
1467
1468
1469 /*
1470  * Module is being unloaded or machine is shutting down. Take care of cleanup.
1471  */
1472 static int
1473 deinit_siftr(void)
1474 {
1475         /* Cleanup. */
1476         siftr_manage_ops(SIFTR_DISABLE);
1477         hashdestroy(counter_hash, M_SIFTR, siftr_hashmask);
1478         mtx_destroy(&siftr_pkt_queue_mtx);
1479         mtx_destroy(&siftr_pkt_mgr_mtx);
1480
1481         return (0);
1482 }
1483
1484
1485 /*
1486  * Module has just been loaded into the kernel.
1487  */
1488 static int
1489 init_siftr(void)
1490 {
1491         EVENTHANDLER_REGISTER(shutdown_pre_sync, siftr_shutdown_handler, NULL,
1492             SHUTDOWN_PRI_FIRST);
1493
1494         /* Initialise our flow counter hash table. */
1495         counter_hash = hashinit(SIFTR_EXPECTED_MAX_TCP_FLOWS, M_SIFTR,
1496             &siftr_hashmask);
1497
1498         mtx_init(&siftr_pkt_queue_mtx, "siftr_pkt_queue_mtx", NULL, MTX_DEF);
1499         mtx_init(&siftr_pkt_mgr_mtx, "siftr_pkt_mgr_mtx", NULL, MTX_DEF);
1500
1501         /* Print message to the user's current terminal. */
1502         uprintf("\nStatistical Information For TCP Research (SIFTR) %s\n"
1503             "          http://caia.swin.edu.au/urp/newtcp\n\n",
1504             MODVERSION_STR);
1505
1506         return (0);
1507 }
1508
1509
1510 /*
1511  * This is the function that is called to load and unload the module.
1512  * When the module is loaded, this function is called once with
1513  * "what" == MOD_LOAD
1514  * When the module is unloaded, this function is called twice with
1515  * "what" = MOD_QUIESCE first, followed by "what" = MOD_UNLOAD second
1516  * When the system is shut down e.g. CTRL-ALT-DEL or using the shutdown command,
1517  * this function is called once with "what" = MOD_SHUTDOWN
1518  * When the system is shut down, the handler isn't called until the very end
1519  * of the shutdown sequence i.e. after the disks have been synced.
1520  */
1521 static int
1522 siftr_load_handler(module_t mod, int what, void *arg)
1523 {
1524         int ret;
1525
1526         switch (what) {
1527         case MOD_LOAD:
1528                 ret = init_siftr();
1529                 break;
1530
1531         case MOD_QUIESCE:
1532         case MOD_SHUTDOWN:
1533                 ret = deinit_siftr();
1534                 break;
1535
1536         case MOD_UNLOAD:
1537                 ret = 0;
1538                 break;
1539
1540         default:
1541                 ret = EINVAL;
1542                 break;
1543         }
1544
1545         return (ret);
1546 }
1547
1548
1549 static moduledata_t siftr_mod = {
1550         .name = "siftr",
1551         .evhand = siftr_load_handler,
1552 };
1553
1554 /*
1555  * Param 1: name of the kernel module
1556  * Param 2: moduledata_t struct containing info about the kernel module
1557  *          and the execution entry point for the module
1558  * Param 3: From sysinit_sub_id enumeration in /usr/include/sys/kernel.h
1559  *          Defines the module initialisation order
1560  * Param 4: From sysinit_elem_order enumeration in /usr/include/sys/kernel.h
1561  *          Defines the initialisation order of this kld relative to others
1562  *          within the same subsystem as defined by param 3
1563  */
1564 DECLARE_MODULE(siftr, siftr_mod, SI_SUB_LAST, SI_ORDER_ANY);
1565 MODULE_DEPEND(siftr, alq, 1, 1, 1);
1566 MODULE_VERSION(siftr, MODVERSION);