release/src/router/busybox/libbb/xconnect.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Connect to host at port using address resolution from getaddrinfo
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this source tree.
   8  */
   9
  10 #include <sys/types.h>
  11 #include <sys/socket.h> /* netinet/in.h needs it */
  12 #include <netinet/in.h>
  13 #include <net/if.h>
  14 #include <sys/un.h>
  15 #include "libbb.h"
  16
  17 int FAST_FUNC setsockopt_int(int fd, int level, int optname, int optval)
  18 {
  19         return setsockopt(fd, level, optname, &optval, sizeof(int));
  20 }
  21 int FAST_FUNC setsockopt_1(int fd, int level, int optname)
  22 {
  23         return setsockopt_int(fd, level, optname, 1);
  24 }
  25 int FAST_FUNC setsockopt_SOL_SOCKET_int(int fd, int optname, int optval)
  26 {
  27         return setsockopt_int(fd, SOL_SOCKET, optname, optval);
  28 }
  29 int FAST_FUNC setsockopt_SOL_SOCKET_1(int fd, int optname)
  30 {
  31         return setsockopt_SOL_SOCKET_int(fd, optname, 1);
  32 }
  33
  34 void FAST_FUNC setsockopt_reuseaddr(int fd)
  35 {
  36         setsockopt_SOL_SOCKET_1(fd, SO_REUSEADDR);
  37 }
  38 int FAST_FUNC setsockopt_broadcast(int fd)
  39 {
  40         return setsockopt_SOL_SOCKET_1(fd, SO_BROADCAST);
  41 }
  42 int FAST_FUNC setsockopt_keepalive(int fd)
  43 {
  44         return setsockopt_SOL_SOCKET_1(fd, SO_KEEPALIVE);
  45 }
  46
  47 #ifdef SO_BINDTODEVICE
  48 int FAST_FUNC setsockopt_bindtodevice(int fd, const char *iface)
  49 {
  50         int r;
  51         struct ifreq ifr;
  52         strncpy_IFNAMSIZ(ifr.ifr_name, iface);
  53         /* NB: passing (iface, strlen(iface) + 1) does not work!
  54          * (maybe it works on _some_ kernels, but not on 2.6.26)
  55          * Actually, ifr_name is at offset 0, and in practice
  56          * just giving char[IFNAMSIZ] instead of struct ifreq works too.
  57          * But just in case it's not true on some obscure arch... */
  58         r = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
  59         if (r)
  60                 bb_perror_msg("can't bind to interface %s", iface);
  61         return r;
  62 }
  63 #else
  64 int FAST_FUNC setsockopt_bindtodevice(int fd UNUSED_PARAM,
  65                 const char *iface UNUSED_PARAM)
  66 {
  67         bb_error_msg("SO_BINDTODEVICE is not supported on this system");
  68         return -1;
  69 }
  70 #endif
  71
  72 static len_and_sockaddr* get_lsa(int fd, int (*get_name)(int fd, struct sockaddr *addr, socklen_t *addrlen))
  73 {
  74         len_and_sockaddr lsa;
  75         len_and_sockaddr *lsa_ptr;
  76
  77         lsa.len = LSA_SIZEOF_SA;
  78         if (get_name(fd, &lsa.u.sa, &lsa.len) != 0)
  79                 return NULL;
  80
  81         lsa_ptr = xzalloc(LSA_LEN_SIZE + lsa.len);
  82         if (lsa.len > LSA_SIZEOF_SA) { /* rarely (if ever) happens */
  83                 lsa_ptr->len = lsa.len;
  84                 get_name(fd, &lsa_ptr->u.sa, &lsa_ptr->len);
  85         } else {
  86                 memcpy(lsa_ptr, &lsa, LSA_LEN_SIZE + lsa.len);
  87         }
  88         return lsa_ptr;
  89 }
  90
  91 len_and_sockaddr* FAST_FUNC get_sock_lsa(int fd)
  92 {
  93         return get_lsa(fd, getsockname);
  94 }
  95
  96 len_and_sockaddr* FAST_FUNC get_peer_lsa(int fd)
  97 {
  98         return get_lsa(fd, getpeername);
  99 }
 100
 101 void FAST_FUNC xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
 102 {
 103         if (connect(s, s_addr, addrlen) < 0) {
 104                 if (ENABLE_FEATURE_CLEAN_UP)
 105                         close(s);
 106                 if (s_addr->sa_family == AF_INET)
 107                         bb_perror_msg_and_die("%s (%s)",
 108                                 "can't connect to remote host",
 109                                 inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
 110                 bb_perror_msg_and_die("can't connect to remote host");
 111         }
 112 }
 113
 114 /* Return port number for a service.
 115  * If "port" is a number use it as the port.
 116  * If "port" is a name it is looked up in /etc/services,
 117  * if it isnt found return default_port
 118  */
 119 unsigned FAST_FUNC bb_lookup_port(const char *port, const char *protocol, unsigned default_port)
 120 {
 121         unsigned port_nr = default_port;
 122         if (port) {
 123                 int old_errno;
 124
 125                 /* Since this is a lib function, we're not allowed to reset errno to 0.
 126                  * Doing so could break an app that is deferring checking of errno. */
 127                 old_errno = errno;
 128                 port_nr = bb_strtou(port, NULL, 10);
 129                 if (errno || port_nr > 65535) {
 130                         struct servent *tserv = getservbyname(port, protocol);
 131                         port_nr = default_port;
 132                         if (tserv)
 133                                 port_nr = ntohs(tserv->s_port);
 134                 }
 135                 errno = old_errno;
 136         }
 137         return (uint16_t)port_nr;
 138 }
 139
 140
 141 /* "New" networking API */
 142
 143
 144 int FAST_FUNC get_nport(const struct sockaddr *sa)
 145 {
 146 #if ENABLE_FEATURE_IPV6
 147         if (sa->sa_family == AF_INET6) {
 148                 return ((struct sockaddr_in6*)sa)->sin6_port;
 149         }
 150 #endif
 151         if (sa->sa_family == AF_INET) {
 152                 return ((struct sockaddr_in*)sa)->sin_port;
 153         }
 154         /* What? UNIX socket? IPX?? :) */
 155         return -1;
 156 }
 157
 158 void FAST_FUNC set_nport(struct sockaddr *sa, unsigned port)
 159 {
 160 #if ENABLE_FEATURE_IPV6
 161         if (sa->sa_family == AF_INET6) {
 162                 struct sockaddr_in6 *sin6 = (void*) sa;
 163                 sin6->sin6_port = port;
 164                 return;
 165         }
 166 #endif
 167         if (sa->sa_family == AF_INET) {
 168                 struct sockaddr_in *sin = (void*) sa;
 169                 sin->sin_port = port;
 170                 return;
 171         }
 172         /* What? UNIX socket? IPX?? :) */
 173 }
 174
 175 /* We hijack this constant to mean something else */
 176 /* It doesn't hurt because we will remove this bit anyway */
 177 #define DIE_ON_ERROR AI_CANONNAME
 178
 179 /* host: "1.2.3.4[:port]", "www.google.com[:port]"
 180  * port: if neither of above specifies port # */
 181 static len_and_sockaddr* str2sockaddr(
 182                 const char *host, int port,
 183 IF_FEATURE_IPV6(sa_family_t af,)
 184                 int ai_flags)
 185 {
 186 IF_NOT_FEATURE_IPV6(sa_family_t af = AF_INET;)
 187         int rc;
 188         len_and_sockaddr *r;
 189         struct addrinfo *result = NULL;
 190         struct addrinfo *used_res;
 191         const char *org_host = host; /* only for error msg */
 192         const char *cp;
 193         struct addrinfo hint;
 194
 195         if (ENABLE_FEATURE_UNIX_LOCAL && is_prefixed_with(host, "local:")) {
 196                 struct sockaddr_un *sun;
 197
 198                 r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_un));
 199                 r->len = sizeof(struct sockaddr_un);
 200                 r->u.sa.sa_family = AF_UNIX;
 201                 sun = (struct sockaddr_un *)&r->u.sa;
 202                 safe_strncpy(sun->sun_path, host + 6, sizeof(sun->sun_path));
 203                 return r;
 204         }
 205
 206         r = NULL;
 207
 208         /* Ugly parsing of host:addr */
 209         if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
 210                 /* Even uglier parsing of [xx]:nn */
 211                 host++;
 212                 cp = strchr(host, ']');
 213                 if (!cp || (cp[1] != ':' && cp[1] != '\0')) {
 214                         /* Malformed: must be [xx]:nn or [xx] */
 215                         bb_error_msg("bad address '%s'", org_host);
 216                         if (ai_flags & DIE_ON_ERROR)
 217                                 xfunc_die();
 218                         return NULL;
 219                 }
 220         } else {
 221                 cp = strrchr(host, ':');
 222                 if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
 223                         /* There is more than one ':' (e.g. "::1") */
 224                         cp = NULL; /* it's not a port spec */
 225                 }
 226         }
 227         if (cp) { /* points to ":" or "]:" */
 228                 int sz = cp - host + 1;
 229
 230                 host = safe_strncpy(alloca(sz), host, sz);
 231                 if (ENABLE_FEATURE_IPV6 && *cp != ':') {
 232                         cp++; /* skip ']' */
 233                         if (*cp == '\0') /* [xx] without port */
 234                                 goto skip;
 235                 }
 236                 cp++; /* skip ':' */
 237                 port = bb_strtou(cp, NULL, 10);
 238                 if (errno || (unsigned)port > 0xffff) {
 239                         bb_error_msg("bad port spec '%s'", org_host);
 240                         if (ai_flags & DIE_ON_ERROR)
 241                                 xfunc_die();
 242                         return NULL;
 243                 }
 244  skip: ;
 245         }
 246
 247         /* Next two if blocks allow to skip getaddrinfo()
 248          * in case host name is a numeric IP(v6) address.
 249          * getaddrinfo() initializes DNS resolution machinery,
 250          * scans network config and such - tens of syscalls.
 251          */
 252         /* If we were not asked specifically for IPv6,
 253          * check whether this is a numeric IPv4 */
 254         IF_FEATURE_IPV6(if(af != AF_INET6)) {
 255                 struct in_addr in4;
 256                 if (inet_aton(host, &in4) != 0) {
 257                         r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in));
 258                         r->len = sizeof(struct sockaddr_in);
 259                         r->u.sa.sa_family = AF_INET;
 260                         r->u.sin.sin_addr = in4;
 261                         goto set_port;
 262                 }
 263         }
 264 #if ENABLE_FEATURE_IPV6
 265         /* If we were not asked specifically for IPv4,
 266          * check whether this is a numeric IPv6 */
 267         if (af != AF_INET) {
 268                 struct in6_addr in6;
 269                 if (inet_pton(AF_INET6, host, &in6) > 0) {
 270                         r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in6));
 271                         r->len = sizeof(struct sockaddr_in6);
 272                         r->u.sa.sa_family = AF_INET6;
 273                         r->u.sin6.sin6_addr = in6;
 274                         goto set_port;
 275                 }
 276         }
 277 #endif
 278
 279         memset(&hint, 0 , sizeof(hint));
 280         hint.ai_family = af;
 281         /* Need SOCK_STREAM, or else we get each address thrice (or more)
 282          * for each possible socket type (tcp,udp,raw...): */
 283         hint.ai_socktype = SOCK_STREAM;
 284         hint.ai_flags = ai_flags & ~DIE_ON_ERROR;
 285         rc = getaddrinfo(host, NULL, &hint, &result);
 286         if (rc || !result) {
 287                 bb_error_msg("bad address '%s'", org_host);
 288                 if (ai_flags & DIE_ON_ERROR)
 289                         xfunc_die();
 290                 goto ret;
 291         }
 292         used_res = result;
 293 #if ENABLE_FEATURE_PREFER_IPV4_ADDRESS
 294         while (1) {
 295                 if (used_res->ai_family == AF_INET)
 296                         break;
 297                 used_res = used_res->ai_next;
 298                 if (!used_res) {
 299                         used_res = result;
 300                         break;
 301                 }
 302         }
 303 #endif
 304         r = xmalloc(LSA_LEN_SIZE + used_res->ai_addrlen);
 305         r->len = used_res->ai_addrlen;
 306         memcpy(&r->u.sa, used_res->ai_addr, used_res->ai_addrlen);
 307
 308  set_port:
 309         set_nport(&r->u.sa, htons(port));
 310  ret:
 311         if (result)
 312                 freeaddrinfo(result);
 313         return r;
 314 }
 315 #if !ENABLE_FEATURE_IPV6
 316 #define str2sockaddr(host, port, af, ai_flags) str2sockaddr(host, port, ai_flags)
 317 #endif
 318
 319 #if ENABLE_FEATURE_IPV6
 320 len_and_sockaddr* FAST_FUNC host_and_af2sockaddr(const char *host, int port, sa_family_t af)
 321 {
 322         return str2sockaddr(host, port, af, 0);
 323 }
 324
 325 len_and_sockaddr* FAST_FUNC xhost_and_af2sockaddr(const char *host, int port, sa_family_t af)
 326 {
 327         return str2sockaddr(host, port, af, DIE_ON_ERROR);
 328 }
 329 #endif
 330
 331 len_and_sockaddr* FAST_FUNC host2sockaddr(const char *host, int port)
 332 {
 333         return str2sockaddr(host, port, AF_UNSPEC, 0);
 334 }
 335
 336 len_and_sockaddr* FAST_FUNC xhost2sockaddr(const char *host, int port)
 337 {
 338         return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
 339 }
 340
 341 len_and_sockaddr* FAST_FUNC xdotted2sockaddr(const char *host, int port)
 342 {
 343         return str2sockaddr(host, port, AF_UNSPEC, AI_NUMERICHOST | DIE_ON_ERROR);
 344 }
 345
 346 int FAST_FUNC xsocket_type(len_and_sockaddr **lsap, int family, int sock_type)
 347 {
 348         len_and_sockaddr *lsa;
 349         int fd;
 350         int len;
 351
 352         if (family == AF_UNSPEC) {
 353 #if ENABLE_FEATURE_IPV6
 354                 fd = socket(AF_INET6, sock_type, 0);
 355                 if (fd >= 0) {
 356                         family = AF_INET6;
 357                         goto done;
 358                 }
 359 #endif
 360                 family = AF_INET;
 361         }
 362
 363         fd = xsocket(family, sock_type, 0);
 364
 365         len = sizeof(struct sockaddr_in);
 366         if (family == AF_UNIX)
 367                 len = sizeof(struct sockaddr_un);
 368 #if ENABLE_FEATURE_IPV6
 369         if (family == AF_INET6) {
 370  done:
 371                 len = sizeof(struct sockaddr_in6);
 372         }
 373 #endif
 374         lsa = xzalloc(LSA_LEN_SIZE + len);
 375         lsa->len = len;
 376         lsa->u.sa.sa_family = family;
 377         *lsap = lsa;
 378         return fd;
 379 }
 380
 381 int FAST_FUNC xsocket_stream(len_and_sockaddr **lsap)
 382 {
 383         return xsocket_type(lsap, AF_UNSPEC, SOCK_STREAM);
 384 }
 385
 386 static int create_and_bind_or_die(const char *bindaddr, int port, int sock_type)
 387 {
 388         int fd;
 389         len_and_sockaddr *lsa;
 390
 391         if (bindaddr && bindaddr[0]) {
 392                 lsa = xdotted2sockaddr(bindaddr, port);
 393                 /* user specified bind addr dictates family */
 394                 fd = xsocket(lsa->u.sa.sa_family, sock_type, 0);
 395         } else {
 396                 fd = xsocket_type(&lsa, AF_UNSPEC, sock_type);
 397                 set_nport(&lsa->u.sa, htons(port));
 398         }
 399         setsockopt_reuseaddr(fd);
 400         xbind(fd, &lsa->u.sa, lsa->len);
 401         free(lsa);
 402         return fd;
 403 }
 404
 405 int FAST_FUNC create_and_bind_stream_or_die(const char *bindaddr, int port)
 406 {
 407         return create_and_bind_or_die(bindaddr, port, SOCK_STREAM);
 408 }
 409
 410 int FAST_FUNC create_and_bind_dgram_or_die(const char *bindaddr, int port)
 411 {
 412         return create_and_bind_or_die(bindaddr, port, SOCK_DGRAM);
 413 }
 414
 415
 416 int FAST_FUNC create_and_connect_stream_or_die(const char *peer, int port)
 417 {
 418         int fd;
 419         len_and_sockaddr *lsa;
 420
 421         lsa = xhost2sockaddr(peer, port);
 422         fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
 423         setsockopt_reuseaddr(fd);
 424         xconnect(fd, &lsa->u.sa, lsa->len);
 425         free(lsa);
 426         return fd;
 427 }
 428
 429 int FAST_FUNC xconnect_stream(const len_and_sockaddr *lsa)
 430 {
 431         int fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
 432         xconnect(fd, &lsa->u.sa, lsa->len);
 433         return fd;
 434 }
 435
 436 /* We hijack this constant to mean something else */
 437 /* It doesn't hurt because we will add this bit anyway */
 438 #define IGNORE_PORT NI_NUMERICSERV
 439 static char* FAST_FUNC sockaddr2str(const struct sockaddr *sa, int flags)
 440 {
 441         char host[128];
 442         char serv[16];
 443         int rc;
 444         socklen_t salen;
 445
 446         if (ENABLE_FEATURE_UNIX_LOCAL && sa->sa_family == AF_UNIX) {
 447                 struct sockaddr_un *sun = (struct sockaddr_un *)sa;
 448                 return xasprintf("local:%.*s",
 449                                 (int) sizeof(sun->sun_path),
 450                                 sun->sun_path);
 451         }
 452
 453         salen = LSA_SIZEOF_SA;
 454 #if ENABLE_FEATURE_IPV6
 455         if (sa->sa_family == AF_INET)
 456                 salen = sizeof(struct sockaddr_in);
 457         if (sa->sa_family == AF_INET6)
 458                 salen = sizeof(struct sockaddr_in6);
 459 #endif
 460         rc = getnameinfo(sa, salen,
 461                         host, sizeof(host),
 462         /* can do ((flags & IGNORE_PORT) ? NULL : serv) but why bother? */
 463                         serv, sizeof(serv),
 464                         /* do not resolve port# into service _name_ */
 465                         flags | NI_NUMERICSERV
 466         );
 467         if (rc)
 468                 return NULL;
 469         if (flags & IGNORE_PORT)
 470                 return xstrdup(host);
 471 #if ENABLE_FEATURE_IPV6
 472         if (sa->sa_family == AF_INET6) {
 473                 if (strchr(host, ':')) /* heh, it's not a resolved hostname */
 474                         return xasprintf("[%s]:%s", host, serv);
 475                 /*return xasprintf("%s:%s", host, serv);*/
 476                 /* - fall through instead */
 477         }
 478 #endif
 479         /* For now we don't support anything else, so it has to be INET */
 480         /*if (sa->sa_family == AF_INET)*/
 481                 return xasprintf("%s:%s", host, serv);
 482         /*return xstrdup(host);*/
 483 }
 484
 485 char* FAST_FUNC xmalloc_sockaddr2host(const struct sockaddr *sa)
 486 {
 487         return sockaddr2str(sa, 0);
 488 }
 489
 490 char* FAST_FUNC xmalloc_sockaddr2host_noport(const struct sockaddr *sa)
 491 {
 492         return sockaddr2str(sa, IGNORE_PORT);
 493 }
 494
 495 char* FAST_FUNC xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa)
 496 {
 497         return sockaddr2str(sa, NI_NAMEREQD | IGNORE_PORT);
 498 }
 499 char* FAST_FUNC xmalloc_sockaddr2dotted(const struct sockaddr *sa)
 500 {
 501         return sockaddr2str(sa, NI_NUMERICHOST);
 502 }
 503
 504 char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
 505 {
 506         return sockaddr2str(sa, NI_NUMERICHOST | IGNORE_PORT);
 507 }