granicus.if.org Git - strace/blob - socketutils.c

   1 /*
   2  * Copyright (c) 2014 Zubin Mithra <zubin.mithra@gmail.com>
   3  * Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include "defs.h"
  30 #include <netinet/in.h>
  31 #include <sys/socket.h>
  32 #include <arpa/inet.h>
  33 #include <linux/netlink.h>
  34 #include <linux/sock_diag.h>
  35 #include <linux/inet_diag.h>
  36 #include <linux/unix_diag.h>
  37 #include <linux/rtnetlink.h>
  38
  39 #if !defined NETLINK_SOCK_DIAG && defined NETLINK_INET_DIAG
  40 # define NETLINK_SOCK_DIAG NETLINK_INET_DIAG
  41 #endif
  42
  43 #include <sys/un.h>
  44 #ifndef UNIX_PATH_MAX
  45 # define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) 0)->sun_path)
  46 #endif
  47
  48 typedef struct {
  49         unsigned long inode;
  50         char *details;
  51 } cache_entry;
  52
  53 #define CACHE_SIZE 1024U
  54 static cache_entry cache[CACHE_SIZE];
  55 #define CACHE_MASK (CACHE_SIZE - 1)
  56
  57 static int
  58 cache_and_print_inode_details(const unsigned long inode, char *details)
  59 {
  60         cache_entry *e = &cache[inode & CACHE_MASK];
  61         free(e->details);
  62         e->inode = inode;
  63         e->details = details;
  64
  65         tprints(details);
  66         return 1;
  67 }
  68
  69 bool
  70 print_sockaddr_by_inode_cached(const unsigned long inode)
  71 {
  72         const cache_entry *e = &cache[inode & CACHE_MASK];
  73         if (e && inode == e->inode) {
  74                 tprints(e->details);
  75                 return true;
  76         }
  77         return false;
  78 }
  79
  80 static bool
  81 inet_send_query(const int fd, const int family, const int proto)
  82 {
  83         struct sockaddr_nl nladdr = {
  84                 .nl_family = AF_NETLINK
  85         };
  86         struct {
  87                 struct nlmsghdr nlh;
  88                 struct inet_diag_req_v2 idr;
  89         } req = {
  90                 .nlh = {
  91                         .nlmsg_len = sizeof(req),
  92                         .nlmsg_type = SOCK_DIAG_BY_FAMILY,
  93                         .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST
  94                 },
  95                 .idr = {
  96                         .sdiag_family = family,
  97                         .sdiag_protocol = proto,
  98                         .idiag_states = -1
  99                 }
 100         };
 101         struct iovec iov = {
 102                 .iov_base = &req,
 103                 .iov_len = sizeof(req)
 104         };
 105         struct msghdr msg = {
 106                 .msg_name = (void *) &nladdr,
 107                 .msg_namelen = sizeof(nladdr),
 108                 .msg_iov = &iov,
 109                 .msg_iovlen = 1
 110         };
 111
 112         for (;;) {
 113                 if (sendmsg(fd, &msg, 0) < 0) {
 114                         if (errno == EINTR)
 115                                 continue;
 116                         return false;
 117                 }
 118                 return true;
 119         }
 120 }
 121
 122 static int
 123 inet_parse_response(const char *proto_name, const void *data,
 124                     const int data_len, const unsigned long inode)
 125 {
 126         const struct inet_diag_msg *diag_msg = data;
 127         static const char zero_addr[sizeof(struct in6_addr)];
 128         socklen_t addr_size, text_size;
 129
 130         if (data_len < (int) NLMSG_LENGTH(sizeof(*diag_msg)))
 131                 return -1;
 132         if (diag_msg->idiag_inode != inode)
 133                 return 0;
 134
 135         switch(diag_msg->idiag_family) {
 136                 case AF_INET:
 137                         addr_size = sizeof(struct in_addr);
 138                         text_size = INET_ADDRSTRLEN;
 139                         break;
 140                 case AF_INET6:
 141                         addr_size = sizeof(struct in6_addr);
 142                         text_size = INET6_ADDRSTRLEN;
 143                         break;
 144                 default:
 145                         return -1;
 146         }
 147
 148         char src_buf[text_size];
 149         char *details;
 150
 151         if (!inet_ntop(diag_msg->idiag_family, diag_msg->id.idiag_src,
 152                        src_buf, text_size))
 153                 return -1;
 154
 155         if (diag_msg->id.idiag_dport ||
 156             memcmp(zero_addr, diag_msg->id.idiag_dst, addr_size)) {
 157                 char dst_buf[text_size];
 158
 159                 if (!inet_ntop(diag_msg->idiag_family, diag_msg->id.idiag_dst,
 160                                dst_buf, text_size))
 161                         return -1;
 162
 163                 if (asprintf(&details, "%s:[%s:%u->%s:%u]", proto_name,
 164                              src_buf, ntohs(diag_msg->id.idiag_sport),
 165                              dst_buf, ntohs(diag_msg->id.idiag_dport)) < 0)
 166                         return false;
 167         } else {
 168                 if (asprintf(&details, "%s:[%s:%u]", proto_name, src_buf,
 169                              ntohs(diag_msg->id.idiag_sport)) < 0)
 170                         return false;
 171         }
 172
 173         return cache_and_print_inode_details(inode, details);
 174 }
 175
 176 static bool
 177 receive_responses(const int fd, const unsigned long inode,
 178                   const char *proto_name,
 179                   int (* parser) (const char *, const void *,
 180                                   int, unsigned long))
 181 {
 182         static long buf[8192 / sizeof(long)];
 183         struct sockaddr_nl nladdr = {
 184                 .nl_family = AF_NETLINK
 185         };
 186         struct iovec iov = {
 187                 .iov_base = buf,
 188                 .iov_len = sizeof(buf)
 189         };
 190         int flags = 0;
 191
 192         for (;;) {
 193                 ssize_t ret;
 194                 struct msghdr msg = {
 195                         .msg_name = (void *) &nladdr,
 196                         .msg_namelen = sizeof(nladdr),
 197                         .msg_iov = &iov,
 198                         .msg_iovlen = 1
 199                 };
 200
 201                 ret = recvmsg(fd, &msg, flags);
 202                 if (ret < 0) {
 203                         if (errno == EINTR)
 204                                 continue;
 205                         return false;
 206                 }
 207
 208                 struct nlmsghdr *h = (struct nlmsghdr *) buf;
 209                 if (!NLMSG_OK(h, ret))
 210                         return false;
 211                 for (; NLMSG_OK(h, ret); h = NLMSG_NEXT(h, ret)) {
 212                         if (h->nlmsg_type != SOCK_DIAG_BY_FAMILY)
 213                                 return false;
 214                         int rc = parser(proto_name, NLMSG_DATA(h),
 215                                         h->nlmsg_len, inode);
 216                         if (rc > 0)
 217                                 return true;
 218                         if (rc < 0)
 219                                 return false;
 220                 }
 221                 flags = MSG_DONTWAIT;
 222         }
 223 }
 224
 225 static bool
 226 inet_print(const int fd, const int family, const int protocol,
 227            const unsigned long inode, const char *proto_name)
 228 {
 229         return inet_send_query(fd, family, protocol)
 230                 && receive_responses(fd, inode, proto_name, inet_parse_response);
 231 }
 232
 233 static bool
 234 unix_send_query(const int fd, const unsigned long inode)
 235 {
 236         struct sockaddr_nl nladdr = {
 237                 .nl_family = AF_NETLINK
 238         };
 239         struct {
 240                 struct nlmsghdr nlh;
 241                 struct unix_diag_req udr;
 242         } req = {
 243                 .nlh = {
 244                         .nlmsg_len = sizeof(req),
 245                         .nlmsg_type = SOCK_DIAG_BY_FAMILY,
 246                         .nlmsg_flags = NLM_F_REQUEST
 247                 },
 248                 .udr = {
 249                         .sdiag_family = AF_UNIX,
 250                         .udiag_ino = inode,
 251                         .udiag_states = -1,
 252                         .udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER,
 253                         .udiag_cookie = { ~0U, ~0U }
 254                 }
 255         };
 256         struct iovec iov = {
 257                 .iov_base = &req,
 258                 .iov_len = sizeof(req)
 259         };
 260         struct msghdr msg = {
 261                 .msg_name = (void *) &nladdr,
 262                 .msg_namelen = sizeof(nladdr),
 263                 .msg_iov = &iov,
 264                 .msg_iovlen = 1
 265         };
 266
 267         for (;;) {
 268                 if (sendmsg(fd, &msg, 0) < 0) {
 269                         if (errno == EINTR)
 270                                 continue;
 271                         return false;
 272                 }
 273                 return true;
 274         }
 275 }
 276
 277 static int
 278 unix_parse_response(const char *proto_name, const void *data,
 279                     const int data_len, const unsigned long inode)
 280 {
 281         const struct unix_diag_msg *diag_msg = data;
 282         struct rtattr *attr;
 283         int rta_len = data_len - NLMSG_LENGTH(sizeof(*diag_msg));
 284         uint32_t peer = 0;
 285         size_t path_len = 0;
 286         char path[UNIX_PATH_MAX + 1];
 287
 288         if (rta_len < 0)
 289                 return -1;
 290         if (diag_msg->udiag_ino != inode)
 291                 return 0;
 292         if (diag_msg->udiag_family != AF_UNIX)
 293                 return -1;
 294
 295         for (attr = (struct rtattr *) (diag_msg + 1);
 296              RTA_OK(attr, rta_len);
 297              attr = RTA_NEXT(attr, rta_len)) {
 298                 switch (attr->rta_type) {
 299                 case UNIX_DIAG_NAME:
 300                         if (!path_len) {
 301                                 path_len = RTA_PAYLOAD(attr);
 302                                 if (path_len > UNIX_PATH_MAX)
 303                                         path_len = UNIX_PATH_MAX;
 304                                 memcpy(path, RTA_DATA(attr), path_len);
 305                                 path[path_len] = '\0';
 306                         }
 307                         break;
 308                 case UNIX_DIAG_PEER:
 309                         if (RTA_PAYLOAD(attr) >= 4)
 310                                 peer = *(uint32_t *) RTA_DATA(attr);
 311                         break;
 312                 }
 313         }
 314
 315         /*
 316          * print obtained information in the following format:
 317          * "UNIX:[" SELF_INODE [ "->" PEER_INODE ][ "," SOCKET_FILE ] "]"
 318          */
 319         if (!peer && !path_len)
 320                 return -1;
 321
 322         char peer_str[3 + sizeof(peer) * 3];
 323         if (peer)
 324                 snprintf(peer_str, sizeof(peer_str), "->%u", peer);
 325         else
 326                 peer_str[0] = '\0';
 327
 328         const char *path_str;
 329         if (path_len) {
 330                 char *outstr = alloca(4 * path_len + 4);
 331
 332                 outstr[0] = ',';
 333                 if (path[0] == '\0') {
 334                         outstr[1] = '@';
 335                         string_quote(path + 1, outstr + 2,
 336                                      path_len - 1, QUOTE_0_TERMINATED);
 337                 } else {
 338                         string_quote(path, outstr + 1,
 339                                      path_len, QUOTE_0_TERMINATED);
 340                 }
 341                 path_str = outstr;
 342         } else {
 343                 path_str = "";
 344         }
 345
 346         char *details;
 347         if (asprintf(&details, "%s:[%lu%s%s]", proto_name, inode,
 348                      peer_str, path_str) < 0)
 349                 return -1;
 350
 351         return cache_and_print_inode_details(inode, details);
 352 }
 353
 354 static bool
 355 unix_print(int fd, const unsigned long inode)
 356 {
 357         return unix_send_query(fd, inode)
 358                 && receive_responses(fd, inode, "UNIX", unix_parse_response);
 359 }
 360
 361 /* Given an inode number of a socket, print out the details
 362  * of the ip address and port. */
 363 bool
 364 print_sockaddr_by_inode(const unsigned long inode, const char *proto_name)
 365 {
 366         int fd;
 367         bool r = false;
 368
 369         fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
 370         if (fd < 0)
 371                 return false;
 372
 373         if (proto_name) {
 374                 if (strcmp(proto_name, "TCP") == 0)
 375                         r = inet_print(fd, AF_INET, IPPROTO_TCP, inode, "TCP");
 376                 else if (strcmp(proto_name, "UDP") == 0)
 377                         r = inet_print(fd, AF_INET, IPPROTO_UDP, inode, "UDP");
 378                 else if (strcmp(proto_name, "TCPv6") == 0)
 379                         r = inet_print(fd, AF_INET6, IPPROTO_TCP, inode, "TCPv6");
 380                 else if (strcmp(proto_name, "UDPv6") == 0)
 381                         r = inet_print(fd, AF_INET6, IPPROTO_UDP, inode, "UDPv6");
 382                 else if (strcmp(proto_name, "UNIX") == 0)
 383                         r = unix_print(fd, inode);
 384
 385                 if (!r) {
 386                         tprintf("%s:[%lu]", proto_name, inode);
 387                         r = true;
 388                 }
 389         } else {
 390                 const struct {
 391                         const int family;
 392                         const int protocol;
 393                         const char *name;
 394                 } protocols[] = {
 395                         { AF_INET, IPPROTO_TCP, "TCP" },
 396                         { AF_INET, IPPROTO_UDP, "UDP" },
 397                         { AF_INET6, IPPROTO_TCP, "TCPv6" },
 398                         { AF_INET6, IPPROTO_UDP, "UDPv6" }
 399                 };
 400                 size_t i;
 401
 402                 for (i = 0; i < ARRAY_SIZE(protocols); ++i) {
 403                         if ((r = inet_print(fd, protocols[i].family,
 404                                             protocols[i].protocol, inode,
 405                                             protocols[i].name)))
 406                                 break;
 407                 }
 408         }
 409
 410         close(fd);
 411         return r;
 412 }