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 void FAST_FUNC setsockopt_reuseaddr(int fd)
  18 {
  19         setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &const_int_1, sizeof(const_int_1));
  20 }
  21 int FAST_FUNC setsockopt_broadcast(int fd)
  22 {
  23         return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &const_int_1, sizeof(const_int_1));
  24 }
  25
  26 #ifdef SO_BINDTODEVICE
  27 int FAST_FUNC setsockopt_bindtodevice(int fd, const char *iface)
  28 {
  29         int r;
  30         struct ifreq ifr;
  31         strncpy_IFNAMSIZ(ifr.ifr_name, iface);
  32         /* NB: passing (iface, strlen(iface) + 1) does not work!
  33          * (maybe it works on _some_ kernels, but not on 2.6.26)
  34          * Actually, ifr_name is at offset 0, and in practice
  35          * just giving char[IFNAMSIZ] instead of struct ifreq works too.
  36          * But just in case it's not true on some obscure arch... */
  37         r = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
  38         if (r)
  39                 bb_perror_msg("can't bind to interface %s", iface);
  40         return r;
  41 }
  42 #else
  43 int FAST_FUNC setsockopt_bindtodevice(int fd UNUSED_PARAM,
  44                 const char *iface UNUSED_PARAM)
  45 {
  46         bb_error_msg("SO_BINDTODEVICE is not supported on this system");
  47         return -1;
  48 }
  49 #endif
  50
  51 static len_and_sockaddr* get_lsa(int fd, int (*get_name)(int fd, struct sockaddr *addr, socklen_t *addrlen))
  52 {
  53         len_and_sockaddr lsa;
  54         len_and_sockaddr *lsa_ptr;
  55
  56         lsa.len = LSA_SIZEOF_SA;
  57         if (get_name(fd, &lsa.u.sa, &lsa.len) != 0)
  58                 return NULL;
  59
  60         lsa_ptr = xzalloc(LSA_LEN_SIZE + lsa.len);
  61         if (lsa.len > LSA_SIZEOF_SA) { /* rarely (if ever) happens */
  62                 lsa_ptr->len = lsa.len;
  63                 get_name(fd, &lsa_ptr->u.sa, &lsa_ptr->len);
  64         } else {
  65                 memcpy(lsa_ptr, &lsa, LSA_LEN_SIZE + lsa.len);
  66         }
  67         return lsa_ptr;
  68 }
  69
  70 len_and_sockaddr* FAST_FUNC get_sock_lsa(int fd)
  71 {
  72         return get_lsa(fd, getsockname);
  73 }
  74
  75 len_and_sockaddr* FAST_FUNC get_peer_lsa(int fd)
  76 {
  77         return get_lsa(fd, getpeername);
  78 }
  79
  80 void FAST_FUNC xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
  81 {
  82         if (connect(s, s_addr, addrlen) < 0) {
  83                 if (ENABLE_FEATURE_CLEAN_UP)
  84                         close(s);
  85                 if (s_addr->sa_family == AF_INET)
  86                         bb_perror_msg_and_die("%s (%s)",
  87                                 "can't connect to remote host",
  88                                 inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
  89                 bb_perror_msg_and_die("can't connect to remote host");
  90         }
  91 }
  92
  93 /* Return port number for a service.
  94  * If "port" is a number use it as the port.
  95  * If "port" is a name it is looked up in /etc/services,
  96  * if it isnt found return default_port
  97  */
  98 unsigned FAST_FUNC bb_lookup_port(const char *port, const char *protocol, unsigned default_port)
  99 {
 100         unsigned port_nr = default_port;
 101         if (port) {
 102                 int old_errno;
 103
 104                 /* Since this is a lib function, we're not allowed to reset errno to 0.
 105                  * Doing so could break an app that is deferring checking of errno. */
 106                 old_errno = errno;
 107                 port_nr = bb_strtou(port, NULL, 10);
 108                 if (errno || port_nr > 65535) {
 109                         struct servent *tserv = getservbyname(port, protocol);
 110                         port_nr = default_port;
 111                         if (tserv)
 112                                 port_nr = ntohs(tserv->s_port);
 113                 }
 114                 errno = old_errno;
 115         }
 116         return (uint16_t)port_nr;
 117 }
 118
 119
 120 /* "New" networking API */
 121
 122
 123 int FAST_FUNC get_nport(const struct sockaddr *sa)
 124 {
 125 #if ENABLE_FEATURE_IPV6
 126         if (sa->sa_family == AF_INET6) {
 127                 return ((struct sockaddr_in6*)sa)->sin6_port;
 128         }
 129 #endif
 130         if (sa->sa_family == AF_INET) {
 131                 return ((struct sockaddr_in*)sa)->sin_port;
 132         }
 133         /* What? UNIX socket? IPX?? :) */
 134         return -1;
 135 }
 136
 137 void FAST_FUNC set_nport(struct sockaddr *sa, unsigned port)
 138 {
 139 #if ENABLE_FEATURE_IPV6
 140         if (sa->sa_family == AF_INET6) {
 141                 struct sockaddr_in6 *sin6 = (void*) sa;
 142                 sin6->sin6_port = port;
 143                 return;
 144         }
 145 #endif
 146         if (sa->sa_family == AF_INET) {
 147                 struct sockaddr_in *sin = (void*) sa;
 148                 sin->sin_port = port;
 149                 return;
 150         }
 151         /* What? UNIX socket? IPX?? :) */
 152 }
 153
 154 /* We hijack this constant to mean something else */
 155 /* It doesn't hurt because we will remove this bit anyway */
 156 #define DIE_ON_ERROR AI_CANONNAME
 157
 158 /* host: "1.2.3.4[:port]", "www.google.com[:port]"
 159  * port: if neither of above specifies port # */
 160 static len_and_sockaddr* str2sockaddr(
 161                 const char *host, int port,
 162 IF_FEATURE_IPV6(sa_family_t af,)
 163                 int ai_flags)
 164 {
 165 IF_NOT_FEATURE_IPV6(sa_family_t af = AF_INET;)
 166         int rc;
 167         len_and_sockaddr *r;
 168         struct addrinfo *result = NULL;
 169         struct addrinfo *used_res;
 170         const char *org_host = host; /* only for error msg */
 171         const char *cp;
 172         struct addrinfo hint;
 173
 174         if (ENABLE_FEATURE_UNIX_LOCAL && strncmp(host, "local:", 6) == 0) {
 175                 struct sockaddr_un *sun;
 176
 177                 r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_un));
 178                 r->len = sizeof(struct sockaddr_un);
 179                 r->u.sa.sa_family = AF_UNIX;
 180                 sun = (struct sockaddr_un *)&r->u.sa;
 181                 safe_strncpy(sun->sun_path, host + 6, sizeof(sun->sun_path));
 182                 return r;
 183         }
 184
 185         r = NULL;
 186
 187         /* Ugly parsing of host:addr */
 188         if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
 189                 /* Even uglier parsing of [xx]:nn */
 190                 host++;
 191                 cp = strchr(host, ']');
 192                 if (!cp || (cp[1] != ':' && cp[1] != '\0')) {
 193                         /* Malformed: must be [xx]:nn or [xx] */
 194                         bb_error_msg("bad address '%s'", org_host);
 195                         if (ai_flags & DIE_ON_ERROR)
 196                                 xfunc_die();
 197                         return NULL;
 198                 }
 199         } else {
 200                 cp = strrchr(host, ':');
 201                 if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
 202                         /* There is more than one ':' (e.g. "::1") */
 203                         cp = NULL; /* it's not a port spec */
 204                 }
 205         }
 206         if (cp) { /* points to ":" or "]:" */
 207                 int sz = cp - host + 1;
 208
 209                 host = safe_strncpy(alloca(sz), host, sz);
 210                 if (ENABLE_FEATURE_IPV6 && *cp != ':') {
 211                         cp++; /* skip ']' */
 212                         if (*cp == '\0') /* [xx] without port */
 213                                 goto skip;
 214                 }
 215                 cp++; /* skip ':' */
 216                 port = bb_strtou(cp, NULL, 10);
 217                 if (errno || (unsigned)port > 0xffff) {
 218                         bb_error_msg("bad port spec '%s'", org_host);
 219                         if (ai_flags & DIE_ON_ERROR)
 220                                 xfunc_die();
 221                         return NULL;
 222                 }
 223  skip: ;
 224         }
 225
 226         /* Next two if blocks allow to skip getaddrinfo()
 227          * in case host name is a numeric IP(v6) address.
 228          * getaddrinfo() initializes DNS resolution machinery,
 229          * scans network config and such - tens of syscalls.
 230          */
 231         /* If we were not asked specifically for IPv6,
 232          * check whether this is a numeric IPv4 */
 233         IF_FEATURE_IPV6(if(af != AF_INET6)) {
 234                 struct in_addr in4;
 235                 if (inet_aton(host, &in4) != 0) {
 236                         r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in));
 237                         r->len = sizeof(struct sockaddr_in);
 238                         r->u.sa.sa_family = AF_INET;
 239                         r->u.sin.sin_addr = in4;
 240                         goto set_port;
 241                 }
 242         }
 243 #if ENABLE_FEATURE_IPV6
 244         /* If we were not asked specifically for IPv4,
 245          * check whether this is a numeric IPv6 */
 246         if (af != AF_INET) {
 247                 struct in6_addr in6;
 248                 if (inet_pton(AF_INET6, host, &in6) > 0) {
 249                         r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in6));
 250                         r->len = sizeof(struct sockaddr_in6);
 251                         r->u.sa.sa_family = AF_INET6;
 252                         r->u.sin6.sin6_addr = in6;
 253                         goto set_port;
 254                 }
 255         }
 256 #endif
 257
 258         memset(&hint, 0 , sizeof(hint));
 259         hint.ai_family = af;
 260         /* Need SOCK_STREAM, or else we get each address thrice (or more)
 261          * for each possible socket type (tcp,udp,raw...): */
 262         hint.ai_socktype = SOCK_STREAM;
 263         hint.ai_flags = ai_flags & ~DIE_ON_ERROR;
 264         rc = getaddrinfo(host, NULL, &hint, &result);
 265         if (rc || !result) {
 266                 bb_error_msg("bad address '%s'", org_host);
 267                 if (ai_flags & DIE_ON_ERROR)
 268                         xfunc_die();
 269                 goto ret;
 270         }
 271         used_res = result;
 272 #if ENABLE_FEATURE_PREFER_IPV4_ADDRESS
 273         while (1) {
 274                 if (used_res->ai_family == AF_INET)
 275                         break;
 276                 used_res = used_res->ai_next;
 277                 if (!used_res) {
 278                         used_res = result;
 279                         break;
 280                 }
 281         }
 282 #endif
 283         r = xmalloc(LSA_LEN_SIZE + used_res->ai_addrlen);
 284         r->len = used_res->ai_addrlen;
 285         memcpy(&r->u.sa, used_res->ai_addr, used_res->ai_addrlen);
 286
 287  set_port:
 288         set_nport(&r->u.sa, htons(port));
 289  ret:
 290         if (result)
 291                 freeaddrinfo(result);
 292         return r;
 293 }
 294 #if !ENABLE_FEATURE_IPV6
 295 #define str2sockaddr(host, port, af, ai_flags) str2sockaddr(host, port, ai_flags)
 296 #endif
 297
 298 #if ENABLE_FEATURE_IPV6
 299 len_and_sockaddr* FAST_FUNC host_and_af2sockaddr(const char *host, int port, sa_family_t af)
 300 {
 301         return str2sockaddr(host, port, af, 0);
 302 }
 303
 304 len_and_sockaddr* FAST_FUNC xhost_and_af2sockaddr(const char *host, int port, sa_family_t af)
 305 {
 306         return str2sockaddr(host, port, af, DIE_ON_ERROR);
 307 }
 308 #endif
 309
 310 len_and_sockaddr* FAST_FUNC host2sockaddr(const char *host, int port)
 311 {
 312         return str2sockaddr(host, port, AF_UNSPEC, 0);
 313 }
 314
 315 len_and_sockaddr* FAST_FUNC xhost2sockaddr(const char *host, int port)
 316 {
 317         return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
 318 }
 319
 320 len_and_sockaddr* FAST_FUNC xdotted2sockaddr(const char *host, int port)
 321 {
 322         return str2sockaddr(host, port, AF_UNSPEC, AI_NUMERICHOST | DIE_ON_ERROR);
 323 }
 324
 325 int FAST_FUNC xsocket_type(len_and_sockaddr **lsap, int family, int sock_type)
 326 {
 327         len_and_sockaddr *lsa;
 328         int fd;
 329         int len;
 330
 331         if (family == AF_UNSPEC) {
 332 #if ENABLE_FEATURE_IPV6
 333                 fd = socket(AF_INET6, sock_type, 0);
 334                 if (fd >= 0) {
 335                         family = AF_INET6;
 336                         goto done;
 337                 }
 338 #endif
 339                 family = AF_INET;
 340         }
 341
 342         fd = xsocket(family, sock_type, 0);
 343
 344         len = sizeof(struct sockaddr_in);
 345         if (family == AF_UNIX)
 346                 len = sizeof(struct sockaddr_un);
 347 #if ENABLE_FEATURE_IPV6
 348         if (family == AF_INET6) {
 349  done:
 350                 len = sizeof(struct sockaddr_in6);
 351         }
 352 #endif
 353         lsa = xzalloc(LSA_LEN_SIZE + len);
 354         lsa->len = len;
 355         lsa->u.sa.sa_family = family;
 356         *lsap = lsa;
 357         return fd;
 358 }
 359
 360 int FAST_FUNC xsocket_stream(len_and_sockaddr **lsap)
 361 {
 362         return xsocket_type(lsap, AF_UNSPEC, SOCK_STREAM);
 363 }
 364
 365 static int create_and_bind_or_die(const char *bindaddr, int port, int sock_type)
 366 {
 367         int fd;
 368         len_and_sockaddr *lsa;
 369
 370         if (bindaddr && bindaddr[0]) {
 371                 lsa = xdotted2sockaddr(bindaddr, port);
 372                 /* user specified bind addr dictates family */
 373                 fd = xsocket(lsa->u.sa.sa_family, sock_type, 0);
 374         } else {
 375                 fd = xsocket_type(&lsa, AF_UNSPEC, sock_type);
 376                 set_nport(&lsa->u.sa, htons(port));
 377         }
 378         setsockopt_reuseaddr(fd);
 379         xbind(fd, &lsa->u.sa, lsa->len);
 380         free(lsa);
 381         return fd;
 382 }
 383
 384 int FAST_FUNC create_and_bind_stream_or_die(const char *bindaddr, int port)
 385 {
 386         return create_and_bind_or_die(bindaddr, port, SOCK_STREAM);
 387 }
 388
 389 int FAST_FUNC create_and_bind_dgram_or_die(const char *bindaddr, int port)
 390 {
 391         return create_and_bind_or_die(bindaddr, port, SOCK_DGRAM);
 392 }
 393
 394
 395 int FAST_FUNC create_and_connect_stream_or_die(const char *peer, int port)
 396 {
 397         int fd;
 398         len_and_sockaddr *lsa;
 399
 400         lsa = xhost2sockaddr(peer, port);
 401         fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
 402         setsockopt_reuseaddr(fd);
 403         xconnect(fd, &lsa->u.sa, lsa->len);
 404         free(lsa);
 405         return fd;
 406 }
 407
 408 int FAST_FUNC xconnect_stream(const len_and_sockaddr *lsa)
 409 {
 410         int fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
 411         xconnect(fd, &lsa->u.sa, lsa->len);
 412         return fd;
 413 }
 414
 415 /* We hijack this constant to mean something else */
 416 /* It doesn't hurt because we will add this bit anyway */
 417 #define IGNORE_PORT NI_NUMERICSERV
 418 static char* FAST_FUNC sockaddr2str(const struct sockaddr *sa, int flags)
 419 {
 420         char host[128];
 421         char serv[16];
 422         int rc;
 423         socklen_t salen;
 424
 425         if (ENABLE_FEATURE_UNIX_LOCAL && sa->sa_family == AF_UNIX) {
 426                 struct sockaddr_un *sun = (struct sockaddr_un *)sa;
 427                 return xasprintf("local:%.*s",
 428                                 (int) sizeof(sun->sun_path),
 429                                 sun->sun_path);
 430         }
 431
 432         salen = LSA_SIZEOF_SA;
 433 #if ENABLE_FEATURE_IPV6
 434         if (sa->sa_family == AF_INET)
 435                 salen = sizeof(struct sockaddr_in);
 436         if (sa->sa_family == AF_INET6)
 437                 salen = sizeof(struct sockaddr_in6);
 438 #endif
 439         rc = getnameinfo(sa, salen,
 440                         host, sizeof(host),
 441         /* can do ((flags & IGNORE_PORT) ? NULL : serv) but why bother? */
 442                         serv, sizeof(serv),
 443                         /* do not resolve port# into service _name_ */
 444                         flags | NI_NUMERICSERV
 445         );
 446         if (rc)
 447                 return NULL;
 448         if (flags & IGNORE_PORT)
 449                 return xstrdup(host);
 450 #if ENABLE_FEATURE_IPV6
 451         if (sa->sa_family == AF_INET6) {
 452                 if (strchr(host, ':')) /* heh, it's not a resolved hostname */
 453                         return xasprintf("[%s]:%s", host, serv);
 454                 /*return xasprintf("%s:%s", host, serv);*/
 455                 /* - fall through instead */
 456         }
 457 #endif
 458         /* For now we don't support anything else, so it has to be INET */
 459         /*if (sa->sa_family == AF_INET)*/
 460                 return xasprintf("%s:%s", host, serv);
 461         /*return xstrdup(host);*/
 462 }
 463
 464 char* FAST_FUNC xmalloc_sockaddr2host(const struct sockaddr *sa)
 465 {
 466         return sockaddr2str(sa, 0);
 467 }
 468
 469 char* FAST_FUNC xmalloc_sockaddr2host_noport(const struct sockaddr *sa)
 470 {
 471         return sockaddr2str(sa, IGNORE_PORT);
 472 }
 473
 474 char* FAST_FUNC xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa)
 475 {
 476         return sockaddr2str(sa, NI_NAMEREQD | IGNORE_PORT);
 477 }
 478 char* FAST_FUNC xmalloc_sockaddr2dotted(const struct sockaddr *sa)
 479 {
 480         return sockaddr2str(sa, NI_NUMERICHOST);
 481 }
 482
 483 char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
 484 {
 485         return sockaddr2str(sa, NI_NUMERICHOST | IGNORE_PORT);
 486 }