tests/sys/netinet/ip_reass_test.c

   1 /*-
   2  * Copyright (c) 2018 The FreeBSD Foundation
   3  *
   4  * This software was developed by Mark Johnston under sponsorship from
   5  * the FreeBSD Foundation.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are
   9  * met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/ioctl.h>
  32 #include <sys/socket.h>
  33 #include <sys/sysctl.h>
  34
  35 #include <net/bpf.h>
  36 #include <net/if.h>
  37 #include <netinet/in.h>
  38 #include <netinet/ip.h>
  39 #include <netinet/ip_var.h>
  40
  41 #include <err.h>
  42 #include <errno.h>
  43 #include <fcntl.h>
  44 #include <ifaddrs.h>
  45 #include <stdint.h>
  46 #include <stdlib.h>
  47 #include <time.h>
  48 #include <unistd.h>
  49
  50 #include <atf-c.h>
  51
  52 struct lopacket {
  53         u_int           family;
  54         struct ip       hdr;
  55         char            payload[];
  56 };
  57
  58 static void
  59 update_cksum(struct ip *ip)
  60 {
  61         size_t i;
  62         uint32_t cksum;
  63         uint16_t *cksump;
  64
  65         ip->ip_sum = 0;
  66         cksump = (uint16_t *)ip;
  67         for (cksum = 0, i = 0; i < sizeof(*ip) / sizeof(*cksump); cksump++, i++)
  68                 cksum += ntohs(*cksump);
  69         cksum = (cksum >> 16) + (cksum & 0xffff);
  70         cksum = ~(cksum + (cksum >> 16));
  71         ip->ip_sum = htons((uint16_t)cksum);
  72 }
  73
  74 static struct lopacket *
  75 alloc_lopacket(in_addr_t dstaddr, size_t payloadlen)
  76 {
  77         struct ip *ip;
  78         struct lopacket *packet;
  79         size_t pktlen;
  80
  81         pktlen = sizeof(*packet) + payloadlen;
  82         packet = malloc(pktlen);
  83         ATF_REQUIRE(packet != NULL);
  84
  85         memset(packet, 0, pktlen);
  86         packet->family = AF_INET;
  87
  88         ip = &packet->hdr;
  89         ip->ip_hl = sizeof(struct ip) >> 2;
  90         ip->ip_v = 4;
  91         ip->ip_tos = 0;
  92         ip->ip_len = htons(sizeof(*ip) + payloadlen);
  93         ip->ip_id = 0;
  94         ip->ip_off = 0;
  95         ip->ip_ttl = 1;
  96         ip->ip_p = IPPROTO_IP;
  97         ip->ip_sum = 0;
  98         ip->ip_src.s_addr = dstaddr;
  99         ip->ip_dst.s_addr = dstaddr;
 100         update_cksum(ip);
 101
 102         return (packet);
 103 }
 104
 105 static void
 106 free_lopacket(struct lopacket *packet)
 107 {
 108
 109         free(packet);
 110 }
 111
 112 static void
 113 write_lopacket(int bpffd, struct lopacket *packet)
 114 {
 115         struct timespec ts;
 116         ssize_t n;
 117         size_t len;
 118
 119         len = sizeof(packet->family) + ntohs(packet->hdr.ip_len);
 120         n = write(bpffd, packet, len);
 121         ATF_REQUIRE_MSG(n >= 0, "packet write failed: %s", strerror(errno));
 122         ATF_REQUIRE_MSG((size_t)n == len, "wrote %zd bytes instead of %zu",
 123             n, len);
 124
 125         /*
 126          * Loopback packets are dispatched asynchronously, give netisr some
 127          * time.
 128          */
 129         ts.tv_sec = 0;
 130         ts.tv_nsec = 5000000; /* 5ms */
 131         (void)nanosleep(&ts, NULL);
 132 }
 133
 134 static int
 135 open_lobpf(in_addr_t *addrp)
 136 {
 137         struct ifreq ifr;
 138         struct ifaddrs *ifa, *ifap;
 139         int error, fd;
 140
 141         fd = open("/dev/bpf0", O_RDWR);
 142         if (fd < 0 && errno == ENOENT)
 143                 atf_tc_skip("no BPF device available");
 144         ATF_REQUIRE_MSG(fd >= 0, "open(/dev/bpf0): %s", strerror(errno));
 145
 146         error = getifaddrs(&ifap);
 147         ATF_REQUIRE(error == 0);
 148         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next)
 149                 if ((ifa->ifa_flags & IFF_LOOPBACK) != 0 &&
 150                     ifa->ifa_addr->sa_family == AF_INET)
 151                         break;
 152         if (ifa == NULL)
 153                 atf_tc_skip("no loopback address found");
 154
 155         memset(&ifr, 0, sizeof(ifr));
 156         strlcpy(ifr.ifr_name, ifa->ifa_name, IFNAMSIZ);
 157         error = ioctl(fd, BIOCSETIF, &ifr);
 158         ATF_REQUIRE_MSG(error == 0, "ioctl(BIOCSETIF): %s", strerror(errno));
 159
 160         *addrp = ((struct sockaddr_in *)(void *)ifa->ifa_addr)->sin_addr.s_addr;
 161
 162         freeifaddrs(ifap);
 163
 164         return (fd);
 165 }
 166
 167 static void
 168 get_ipstat(struct ipstat *stat)
 169 {
 170         size_t len;
 171         int error;
 172
 173         memset(stat, 0, sizeof(*stat));
 174         len = sizeof(*stat);
 175         error = sysctlbyname("net.inet.ip.stats", stat, &len, NULL, 0);
 176         ATF_REQUIRE_MSG(error == 0, "sysctl(net.inet.ip.stats) failed: %s",
 177             strerror(errno));
 178         ATF_REQUIRE(len == sizeof(*stat));
 179 }
 180
 181 #define CHECK_IP_COUNTER(oldp, newp, counter)                           \
 182         ATF_REQUIRE_MSG((oldp)->ips_ ## counter < (newp)->ips_ ## counter, \
 183             "ips_" #counter " wasn't incremented (%ju vs. %ju)",        \
 184             (uintmax_t)old.ips_ ## counter, (uintmax_t)new.ips_## counter);
 185
 186 /*
 187  * Make sure a fragment with MF set doesn't come after the last fragment of a
 188  * packet.  Make sure that multiple fragments with MF clear have the same offset
 189  * and length.
 190  */
 191 ATF_TC(ip_reass__multiple_last_fragments);
 192 ATF_TC_HEAD(ip_reass__multiple_last_fragments, tc)
 193 {
 194         atf_tc_set_md_var(tc, "require.user", "root");
 195 }
 196 ATF_TC_BODY(ip_reass__multiple_last_fragments, tc)
 197 {
 198         struct ipstat old, new;
 199         struct ip *ip;
 200         struct lopacket *packet1, *packet2, *packet3, *packet4;
 201         in_addr_t addr;
 202         int error, fd;
 203         uint16_t ipid;
 204
 205         fd = open_lobpf(&addr);
 206         ipid = arc4random_uniform(UINT16_MAX + 1);
 207
 208         packet1 = alloc_lopacket(addr, 16);
 209         ip = &packet1->hdr;
 210         ip->ip_id = ipid;
 211         ip->ip_off = htons(0x10);
 212         update_cksum(ip);
 213
 214         packet2 = alloc_lopacket(addr, 16);
 215         ip = &packet2->hdr;
 216         ip->ip_id = ipid;
 217         ip->ip_off = htons(0x20);
 218         update_cksum(ip);
 219
 220         packet3 = alloc_lopacket(addr, 16);
 221         ip = &packet3->hdr;
 222         ip->ip_id = ipid;
 223         ip->ip_off = htons(0x8);
 224         update_cksum(ip);
 225
 226         packet4 = alloc_lopacket(addr, 32);
 227         ip = &packet4->hdr;
 228         ip->ip_id = ipid;
 229         ip->ip_off = htons(0x10);
 230         update_cksum(ip);
 231
 232         write_lopacket(fd, packet1);
 233
 234         /* packet2 comes after packet1. */
 235         get_ipstat(&old);
 236         write_lopacket(fd, packet2);
 237         get_ipstat(&new);
 238         CHECK_IP_COUNTER(&old, &new, fragdropped);
 239
 240         /* packet2 comes after packet1 and has MF set. */
 241         packet2->hdr.ip_off = htons(IP_MF | 0x20);
 242         update_cksum(&packet2->hdr);
 243         get_ipstat(&old);
 244         write_lopacket(fd, packet2);
 245         get_ipstat(&new);
 246         CHECK_IP_COUNTER(&old, &new, fragdropped);
 247
 248         /* packet3 comes before packet1 but overlaps. */
 249         get_ipstat(&old);
 250         write_lopacket(fd, packet3);
 251         get_ipstat(&new);
 252         CHECK_IP_COUNTER(&old, &new, fragdropped);
 253
 254         /* packet4 has the same offset as packet1 but is longer. */
 255         get_ipstat(&old);
 256         write_lopacket(fd, packet4);
 257         get_ipstat(&new);
 258         CHECK_IP_COUNTER(&old, &new, fragdropped);
 259
 260         error = close(fd);
 261         ATF_REQUIRE(error == 0);
 262         free_lopacket(packet1);
 263         free_lopacket(packet2);
 264         free_lopacket(packet3);
 265         free_lopacket(packet4);
 266 }
 267
 268 /*
 269  * Make sure that we reject zero-length fragments.
 270  */
 271 ATF_TC(ip_reass__zero_length_fragment);
 272 ATF_TC_HEAD(ip_reass__zero_length_fragment, tc)
 273 {
 274         atf_tc_set_md_var(tc, "require.user", "root");
 275 }
 276 ATF_TC_BODY(ip_reass__zero_length_fragment, tc)
 277 {
 278         struct ipstat old, new;
 279         struct ip *ip;
 280         struct lopacket *packet1, *packet2;
 281         in_addr_t addr;
 282         int error, fd;
 283         uint16_t ipid;
 284
 285         fd = open_lobpf(&addr);
 286         ipid = arc4random_uniform(UINT16_MAX + 1);
 287
 288         /*
 289          * Create two packets, one with MF set, one without.
 290          */
 291         packet1 = alloc_lopacket(addr, 0);
 292         ip = &packet1->hdr;
 293         ip->ip_id = ipid;
 294         ip->ip_off = htons(IP_MF | 0x10);
 295         update_cksum(ip);
 296
 297         packet2 = alloc_lopacket(addr, 0);
 298         ip = &packet2->hdr;
 299         ip->ip_id = ~ipid;
 300         ip->ip_off = htons(0x10);
 301         update_cksum(ip);
 302
 303         get_ipstat(&old);
 304         write_lopacket(fd, packet1);
 305         get_ipstat(&new);
 306         CHECK_IP_COUNTER(&old, &new, toosmall);
 307         CHECK_IP_COUNTER(&old, &new, fragdropped);
 308
 309         get_ipstat(&old);
 310         write_lopacket(fd, packet2);
 311         get_ipstat(&new);
 312         CHECK_IP_COUNTER(&old, &new, toosmall);
 313         CHECK_IP_COUNTER(&old, &new, fragdropped);
 314
 315         error = close(fd);
 316         ATF_REQUIRE(error == 0);
 317         free_lopacket(packet1);
 318         free_lopacket(packet2);
 319 }
 320
 321 ATF_TC(ip_reass__large_fragment);
 322 ATF_TC_HEAD(ip_reass__large_fragment, tc)
 323 {
 324         atf_tc_set_md_var(tc, "require.user", "root");
 325 }
 326 ATF_TC_BODY(ip_reass__large_fragment, tc)
 327 {
 328         struct ipstat old, new;
 329         struct ip *ip;
 330         struct lopacket *packet1, *packet2;
 331         in_addr_t addr;
 332         int error, fd;
 333         uint16_t ipid;
 334
 335         fd = open_lobpf(&addr);
 336         ipid = arc4random_uniform(UINT16_MAX + 1);
 337
 338         /*
 339          * Create two packets, one with MF set, one without.
 340          *
 341          * 16 + (0x1fff << 3) > IP_MAXPACKET, so these should fail the check.
 342          */
 343         packet1 = alloc_lopacket(addr, 16);
 344         ip = &packet1->hdr;
 345         ip->ip_id = ipid;
 346         ip->ip_off = htons(IP_MF | 0x1fff);
 347         update_cksum(ip);
 348
 349         packet2 = alloc_lopacket(addr, 16);
 350         ip = &packet2->hdr;
 351         ip->ip_id = ipid;
 352         ip->ip_off = htons(0x1fff);
 353         update_cksum(ip);
 354
 355         get_ipstat(&old);
 356         write_lopacket(fd, packet1);
 357         get_ipstat(&new);
 358         CHECK_IP_COUNTER(&old, &new, toolong);
 359         CHECK_IP_COUNTER(&old, &new, fragdropped);
 360
 361         get_ipstat(&old);
 362         write_lopacket(fd, packet2);
 363         get_ipstat(&new);
 364         CHECK_IP_COUNTER(&old, &new, toolong);
 365         CHECK_IP_COUNTER(&old, &new, fragdropped);
 366
 367         error = close(fd);
 368         ATF_REQUIRE(error == 0);
 369         free_lopacket(packet1);
 370         free_lopacket(packet2);
 371 }
 372
 373 ATF_TP_ADD_TCS(tp)
 374 {
 375         ATF_TP_ADD_TC(tp, ip_reass__multiple_last_fragments);
 376         ATF_TP_ADD_TC(tp, ip_reass__zero_length_fragment);
 377         ATF_TP_ADD_TC(tp, ip_reass__large_fragment);
 378
 379         return (atf_no_error());
 380 }