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/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #include <sys/param.h>
  34 #include <sys/ioctl.h>
  35 #include <sys/socket.h>
  36 #include <sys/sysctl.h>
  37
  38 #include <net/bpf.h>
  39 #include <net/if.h>
  40 #include <netinet/in.h>
  41 #include <netinet/ip.h>
  42 #include <netinet/ip_var.h>
  43
  44 #include <err.h>
  45 #include <errno.h>
  46 #include <fcntl.h>
  47 #include <ifaddrs.h>
  48 #include <stdint.h>
  49 #include <stdlib.h>
  50 #include <time.h>
  51 #include <unistd.h>
  52
  53 #include <atf-c.h>
  54
  55 struct lopacket {
  56         u_int           family;
  57         struct ip       hdr;
  58         char            payload[];
  59 };
  60
  61 static void
  62 update_cksum(struct ip *ip)
  63 {
  64         size_t i;
  65         uint32_t cksum;
  66         uint16_t *cksump;
  67
  68         ip->ip_sum = 0;
  69         cksump = (uint16_t *)ip;
  70         for (cksum = 0, i = 0; i < sizeof(*ip) / sizeof(*cksump); cksump++, i++)
  71                 cksum += ntohs(*cksump);
  72         cksum = (cksum >> 16) + (cksum & 0xffff);
  73         cksum = ~(cksum + (cksum >> 16));
  74         ip->ip_sum = htons((uint16_t)cksum);
  75 }
  76
  77 static struct lopacket *
  78 alloc_lopacket(in_addr_t dstaddr, size_t payloadlen)
  79 {
  80         struct ip *ip;
  81         struct lopacket *packet;
  82         size_t pktlen;
  83
  84         pktlen = sizeof(*packet) + payloadlen;
  85         packet = malloc(pktlen);
  86         ATF_REQUIRE(packet != NULL);
  87
  88         memset(packet, 0, pktlen);
  89         packet->family = AF_INET;
  90
  91         ip = &packet->hdr;
  92         ip->ip_hl = sizeof(struct ip) >> 2;
  93         ip->ip_v = 4;
  94         ip->ip_tos = 0;
  95         ip->ip_len = htons(sizeof(*ip) + payloadlen);
  96         ip->ip_id = 0;
  97         ip->ip_off = 0;
  98         ip->ip_ttl = 1;
  99         ip->ip_p = IPPROTO_IP;
 100         ip->ip_sum = 0;
 101         ip->ip_src.s_addr = dstaddr;
 102         ip->ip_dst.s_addr = dstaddr;
 103         update_cksum(ip);
 104
 105         return (packet);
 106 }
 107
 108 static void
 109 free_lopacket(struct lopacket *packet)
 110 {
 111
 112         free(packet);
 113 }
 114
 115 static void
 116 write_lopacket(int bpffd, struct lopacket *packet)
 117 {
 118         struct timespec ts;
 119         ssize_t n;
 120         size_t len;
 121
 122         len = sizeof(packet->family) + ntohs(packet->hdr.ip_len);
 123         n = write(bpffd, packet, len);
 124         ATF_REQUIRE_MSG(n >= 0, "packet write failed: %s", strerror(errno));
 125         ATF_REQUIRE_MSG((size_t)n == len, "wrote %zd bytes instead of %zu",
 126             n, len);
 127
 128         /*
 129          * Loopback packets are dispatched asynchronously, give netisr some
 130          * time.
 131          */
 132         ts.tv_sec = 0;
 133         ts.tv_nsec = 5000000; /* 5ms */
 134         (void)nanosleep(&ts, NULL);
 135 }
 136
 137 static int
 138 open_lobpf(in_addr_t *addrp)
 139 {
 140         struct ifreq ifr;
 141         struct ifaddrs *ifa, *ifap;
 142         int error, fd;
 143
 144         fd = open("/dev/bpf0", O_RDWR);
 145         if (fd < 0 && errno == ENOENT)
 146                 atf_tc_skip("no BPF device available");
 147         ATF_REQUIRE_MSG(fd >= 0, "open(/dev/bpf0): %s", strerror(errno));
 148
 149         error = getifaddrs(&ifap);
 150         ATF_REQUIRE(error == 0);
 151         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next)
 152                 if ((ifa->ifa_flags & IFF_LOOPBACK) != 0 &&
 153                     ifa->ifa_addr->sa_family == AF_INET)
 154                         break;
 155         if (ifa == NULL)
 156                 atf_tc_skip("no loopback address found");
 157
 158         memset(&ifr, 0, sizeof(ifr));
 159         strlcpy(ifr.ifr_name, ifa->ifa_name, IFNAMSIZ);
 160         error = ioctl(fd, BIOCSETIF, &ifr);
 161         ATF_REQUIRE_MSG(error == 0, "ioctl(BIOCSETIF): %s", strerror(errno));
 162
 163         *addrp = ((struct sockaddr_in *)(void *)ifa->ifa_addr)->sin_addr.s_addr;
 164
 165         freeifaddrs(ifap);
 166
 167         return (fd);
 168 }
 169
 170 static void
 171 get_ipstat(struct ipstat *stat)
 172 {
 173         size_t len;
 174         int error;
 175
 176         memset(stat, 0, sizeof(*stat));
 177         len = sizeof(*stat);
 178         error = sysctlbyname("net.inet.ip.stats", stat, &len, NULL, 0);
 179         ATF_REQUIRE_MSG(error == 0, "sysctl(net.inet.ip.stats) failed: %s",
 180             strerror(errno));
 181         ATF_REQUIRE(len == sizeof(*stat));
 182 }
 183
 184 #define CHECK_IP_COUNTER(oldp, newp, counter)                           \
 185         ATF_REQUIRE_MSG((oldp)->ips_ ## counter < (newp)->ips_ ## counter, \
 186             "ips_" #counter " wasn't incremented (%ju vs. %ju)",        \
 187             (uintmax_t)old.ips_ ## counter, (uintmax_t)new.ips_## counter);
 188
 189 /*
 190  * Make sure a fragment with MF set doesn't come after the last fragment of a
 191  * packet.  Make sure that multiple fragments with MF clear have the same offset
 192  * and length.
 193  */
 194 ATF_TC(ip_reass__multiple_last_fragments);
 195 ATF_TC_HEAD(ip_reass__multiple_last_fragments, tc)
 196 {
 197         atf_tc_set_md_var(tc, "require.user", "root");
 198 }
 199 ATF_TC_BODY(ip_reass__multiple_last_fragments, tc)
 200 {
 201         struct ipstat old, new;
 202         struct ip *ip;
 203         struct lopacket *packet1, *packet2, *packet3, *packet4;
 204         in_addr_t addr;
 205         int error, fd;
 206         uint16_t ipid;
 207
 208         fd = open_lobpf(&addr);
 209         ipid = arc4random_uniform(UINT16_MAX + 1);
 210
 211         packet1 = alloc_lopacket(addr, 16);
 212         ip = &packet1->hdr;
 213         ip->ip_id = ipid;
 214         ip->ip_off = htons(0x10);
 215         update_cksum(ip);
 216
 217         packet2 = alloc_lopacket(addr, 16);
 218         ip = &packet2->hdr;
 219         ip->ip_id = ipid;
 220         ip->ip_off = htons(0x20);
 221         update_cksum(ip);
 222
 223         packet3 = alloc_lopacket(addr, 16);
 224         ip = &packet3->hdr;
 225         ip->ip_id = ipid;
 226         ip->ip_off = htons(0x8);
 227         update_cksum(ip);
 228
 229         packet4 = alloc_lopacket(addr, 32);
 230         ip = &packet4->hdr;
 231         ip->ip_id = ipid;
 232         ip->ip_off = htons(0x10);
 233         update_cksum(ip);
 234
 235         write_lopacket(fd, packet1);
 236
 237         /* packet2 comes after packet1. */
 238         get_ipstat(&old);
 239         write_lopacket(fd, packet2);
 240         get_ipstat(&new);
 241         CHECK_IP_COUNTER(&old, &new, fragdropped);
 242
 243         /* packet2 comes after packet1 and has MF set. */
 244         packet2->hdr.ip_off = htons(IP_MF | 0x20);
 245         update_cksum(&packet2->hdr);
 246         get_ipstat(&old);
 247         write_lopacket(fd, packet2);
 248         get_ipstat(&new);
 249         CHECK_IP_COUNTER(&old, &new, fragdropped);
 250
 251         /* packet3 comes before packet1 but overlaps. */
 252         get_ipstat(&old);
 253         write_lopacket(fd, packet3);
 254         get_ipstat(&new);
 255         CHECK_IP_COUNTER(&old, &new, fragdropped);
 256
 257         /* packet4 has the same offset as packet1 but is longer. */
 258         get_ipstat(&old);
 259         write_lopacket(fd, packet4);
 260         get_ipstat(&new);
 261         CHECK_IP_COUNTER(&old, &new, fragdropped);
 262
 263         error = close(fd);
 264         ATF_REQUIRE(error == 0);
 265         free_lopacket(packet1);
 266         free_lopacket(packet2);
 267 }
 268
 269 /*
 270  * Make sure that we reject zero-length fragments.
 271  */
 272 ATF_TC(ip_reass__zero_length_fragment);
 273 ATF_TC_HEAD(ip_reass__zero_length_fragment, tc)
 274 {
 275         atf_tc_set_md_var(tc, "require.user", "root");
 276 }
 277 ATF_TC_BODY(ip_reass__zero_length_fragment, tc)
 278 {
 279         struct ipstat old, new;
 280         struct ip *ip;
 281         struct lopacket *packet1, *packet2;
 282         in_addr_t addr;
 283         int error, fd;
 284         uint16_t ipid;
 285
 286         fd = open_lobpf(&addr);
 287         ipid = arc4random_uniform(UINT16_MAX + 1);
 288
 289         /*
 290          * Create two packets, one with MF set, one without.
 291          */
 292         packet1 = alloc_lopacket(addr, 0);
 293         ip = &packet1->hdr;
 294         ip->ip_id = ipid;
 295         ip->ip_off = htons(IP_MF | 0x10);
 296         update_cksum(ip);
 297
 298         packet2 = alloc_lopacket(addr, 0);
 299         ip = &packet2->hdr;
 300         ip->ip_id = ~ipid;
 301         ip->ip_off = htons(0x10);
 302         update_cksum(ip);
 303
 304         get_ipstat(&old);
 305         write_lopacket(fd, packet1);
 306         get_ipstat(&new);
 307         CHECK_IP_COUNTER(&old, &new, toosmall);
 308         CHECK_IP_COUNTER(&old, &new, fragdropped);
 309
 310         get_ipstat(&old);
 311         write_lopacket(fd, packet2);
 312         get_ipstat(&new);
 313         CHECK_IP_COUNTER(&old, &new, toosmall);
 314         CHECK_IP_COUNTER(&old, &new, fragdropped);
 315
 316         error = close(fd);
 317         ATF_REQUIRE(error == 0);
 318         free_lopacket(packet1);
 319         free_lopacket(packet2);
 320 }
 321
 322 ATF_TC(ip_reass__large_fragment);
 323 ATF_TC_HEAD(ip_reass__large_fragment, tc)
 324 {
 325         atf_tc_set_md_var(tc, "require.user", "root");
 326 }
 327 ATF_TC_BODY(ip_reass__large_fragment, tc)
 328 {
 329         struct ipstat old, new;
 330         struct ip *ip;
 331         struct lopacket *packet1, *packet2;
 332         in_addr_t addr;
 333         int error, fd;
 334         uint16_t ipid;
 335
 336         fd = open_lobpf(&addr);
 337         ipid = arc4random_uniform(UINT16_MAX + 1);
 338
 339         /*
 340          * Create two packets, one with MF set, one without.
 341          *
 342          * 16 + (0x1fff << 3) > IP_MAXPACKET, so these should fail the check.
 343          */
 344         packet1 = alloc_lopacket(addr, 16);
 345         ip = &packet1->hdr;
 346         ip->ip_id = ipid;
 347         ip->ip_off = htons(IP_MF | 0x1fff);
 348         update_cksum(ip);
 349
 350         packet2 = alloc_lopacket(addr, 16);
 351         ip = &packet2->hdr;
 352         ip->ip_id = ipid;
 353         ip->ip_off = htons(0x1fff);
 354         update_cksum(ip);
 355
 356         get_ipstat(&old);
 357         write_lopacket(fd, packet1);
 358         get_ipstat(&new);
 359         CHECK_IP_COUNTER(&old, &new, toolong);
 360         CHECK_IP_COUNTER(&old, &new, fragdropped);
 361
 362         get_ipstat(&old);
 363         write_lopacket(fd, packet2);
 364         get_ipstat(&new);
 365         CHECK_IP_COUNTER(&old, &new, toolong);
 366         CHECK_IP_COUNTER(&old, &new, fragdropped);
 367
 368         error = close(fd);
 369         ATF_REQUIRE(error == 0);
 370         free_lopacket(packet1);
 371         free_lopacket(packet2);
 372 }
 373
 374 ATF_TP_ADD_TCS(tp)
 375 {
 376         ATF_TP_ADD_TC(tp, ip_reass__multiple_last_fragments);
 377         ATF_TP_ADD_TC(tp, ip_reass__zero_length_fragment);
 378         ATF_TP_ADD_TC(tp, ip_reass__large_fragment);
 379
 380         return (atf_no_error());
 381 }