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 tarball for details.
   8  */
   9
  10 #include <netinet/in.h>
  11 #include <net/if.h>
  12 #include "libbb.h"
  13
  14 void FAST_FUNC setsockopt_reuseaddr(int fd)
  15 {
  16         setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &const_int_1, sizeof(const_int_1));
  17 }
  18 int FAST_FUNC setsockopt_broadcast(int fd)
  19 {
  20         return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &const_int_1, sizeof(const_int_1));
  21 }
  22 int FAST_FUNC setsockopt_bindtodevice(int fd, const char *iface)
  23 {
  24         int r;
  25         struct ifreq ifr;
  26         strncpy_IFNAMSIZ(ifr.ifr_name, iface);
  27         /* NB: passing (iface, strlen(iface) + 1) does not work!
  28          * (maybe it works on _some_ kernels, but not on 2.6.26)
  29          * Actually, ifr_name is at offset 0, and in practice
  30          * just giving char[IFNAMSIZ] instead of struct ifreq works too.
  31          * But just in case it's not true on some obscure arch... */
  32         r = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
  33         if (r)
  34                 bb_perror_msg("can't bind to interface %s", iface);
  35         return r;
  36 }
  37
  38 len_and_sockaddr* FAST_FUNC get_sock_lsa(int fd)
  39 {
  40         len_and_sockaddr *lsa;
  41         socklen_t len = 0;
  42
  43         /* Can be optimized to do only one getsockname() */
  44         if (getsockname(fd, NULL, &len) != 0)
  45                 return NULL;
  46         lsa = xzalloc(LSA_LEN_SIZE + len);
  47         lsa->len = len;
  48         getsockname(fd, &lsa->u.sa, &lsa->len);
  49         return lsa;
  50 }
  51
  52 void FAST_FUNC xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
  53 {
  54         if (connect(s, s_addr, addrlen) < 0) {
  55                 if (ENABLE_FEATURE_CLEAN_UP)
  56                         close(s);
  57                 if (s_addr->sa_family == AF_INET)
  58                         bb_perror_msg_and_die("%s (%s)",
  59                                 "cannot connect to remote host",
  60                                 inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
  61                 bb_perror_msg_and_die("cannot connect to remote host");
  62         }
  63 }
  64
  65 /* Return port number for a service.
  66  * If "port" is a number use it as the port.
  67  * If "port" is a name it is looked up in /etc/services,
  68  * if it isnt found return default_port
  69  */
  70 unsigned FAST_FUNC bb_lookup_port(const char *port, const char *protocol, unsigned default_port)
  71 {
  72         unsigned port_nr = default_port;
  73         if (port) {
  74                 int old_errno;
  75
  76                 /* Since this is a lib function, we're not allowed to reset errno to 0.
  77                  * Doing so could break an app that is deferring checking of errno. */
  78                 old_errno = errno;
  79                 port_nr = bb_strtou(port, NULL, 10);
  80                 if (errno || port_nr > 65535) {
  81                         struct servent *tserv = getservbyname(port, protocol);
  82                         port_nr = default_port;
  83                         if (tserv)
  84                                 port_nr = ntohs(tserv->s_port);
  85                 }
  86                 errno = old_errno;
  87         }
  88         return (uint16_t)port_nr;
  89 }
  90
  91
  92 /* "Old" networking API - only IPv4 */
  93
  94 /*
  95 void FAST_FUNC bb_lookup_host(struct sockaddr_in *s_in, const char *host)
  96 {
  97         struct hostent *he;
  98
  99         memset(s_in, 0, sizeof(struct sockaddr_in));
 100         s_in->sin_family = AF_INET;
 101         he = xgethostbyname(host);
 102         memcpy(&(s_in->sin_addr), he->h_addr_list[0], he->h_length);
 103 }
 104
 105
 106 int FAST_FUNC xconnect_tcp_v4(struct sockaddr_in *s_addr)
 107 {
 108         int s = xsocket(AF_INET, SOCK_STREAM, 0);
 109         xconnect(s, (struct sockaddr*) s_addr, sizeof(*s_addr));
 110         return s;
 111 }
 112 */
 113
 114 /* "New" networking API */
 115
 116
 117 int FAST_FUNC get_nport(const struct sockaddr *sa)
 118 {
 119 #if ENABLE_FEATURE_IPV6
 120         if (sa->sa_family == AF_INET6) {
 121                 return ((struct sockaddr_in6*)sa)->sin6_port;
 122         }
 123 #endif
 124         if (sa->sa_family == AF_INET) {
 125                 return ((struct sockaddr_in*)sa)->sin_port;
 126         }
 127         /* What? UNIX socket? IPX?? :) */
 128         return -1;
 129 }
 130
 131 void FAST_FUNC set_nport(len_and_sockaddr *lsa, unsigned port)
 132 {
 133 #if ENABLE_FEATURE_IPV6
 134         if (lsa->u.sa.sa_family == AF_INET6) {
 135                 lsa->u.sin6.sin6_port = port;
 136                 return;
 137         }
 138 #endif
 139         if (lsa->u.sa.sa_family == AF_INET) {
 140                 lsa->u.sin.sin_port = port;
 141                 return;
 142         }
 143         /* What? UNIX socket? IPX?? :) */
 144 }
 145
 146 /* We hijack this constant to mean something else */
 147 /* It doesn't hurt because we will remove this bit anyway */
 148 #define DIE_ON_ERROR AI_CANONNAME
 149
 150 /* host: "1.2.3.4[:port]", "www.google.com[:port]"
 151  * port: if neither of above specifies port # */
 152 static len_and_sockaddr* str2sockaddr(
 153                 const char *host, int port,
 154 USE_FEATURE_IPV6(sa_family_t af,)
 155                 int ai_flags)
 156 {
 157         int rc;
 158         len_and_sockaddr *r = NULL;
 159         struct addrinfo *result = NULL;
 160         struct addrinfo *used_res;
 161         const char *org_host = host; /* only for error msg */
 162         const char *cp;
 163         struct addrinfo hint;
 164
 165         /* Ugly parsing of host:addr */
 166         if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
 167                 /* Even uglier parsing of [xx]:nn */
 168                 host++;
 169                 cp = strchr(host, ']');
 170                 if (!cp || (cp[1] != ':' && cp[1] != '\0')) {
 171                         /* Malformed: must be [xx]:nn or [xx] */
 172                         bb_error_msg("bad address '%s'", org_host);
 173                         if (ai_flags & DIE_ON_ERROR)
 174                                 xfunc_die();
 175                         return NULL;
 176                 }
 177         } else {
 178                 cp = strrchr(host, ':');
 179                 if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
 180                         /* There is more than one ':' (e.g. "::1") */
 181                         cp = NULL; /* it's not a port spec */
 182                 }
 183         }
 184         if (cp) { /* points to ":" or "]:" */
 185                 int sz = cp - host + 1;
 186                 host = safe_strncpy(alloca(sz), host, sz);
 187                 if (ENABLE_FEATURE_IPV6 && *cp != ':') {
 188                         cp++; /* skip ']' */
 189                         if (*cp == '\0') /* [xx] without port */
 190                                 goto skip;
 191                 }
 192                 cp++; /* skip ':' */
 193                 port = bb_strtou(cp, NULL, 10);
 194                 if (errno || (unsigned)port > 0xffff) {
 195                         bb_error_msg("bad port spec '%s'", org_host);
 196                         if (ai_flags & DIE_ON_ERROR)
 197                                 xfunc_die();
 198                         return NULL;
 199                 }
 200  skip: ;
 201         }
 202
 203         memset(&hint, 0 , sizeof(hint));
 204 #if !ENABLE_FEATURE_IPV6
 205         hint.ai_family = AF_INET; /* do not try to find IPv6 */
 206 #else
 207         hint.ai_family = af;
 208 #endif
 209         /* Needed. Or else we will get each address thrice (or more)
 210          * for each possible socket type (tcp,udp,raw...): */
 211         hint.ai_socktype = SOCK_STREAM;
 212         hint.ai_flags = ai_flags & ~DIE_ON_ERROR;
 213         rc = getaddrinfo(host, NULL, &hint, &result);
 214         if (rc || !result) {
 215                 bb_error_msg("bad address '%s'", org_host);
 216                 if (ai_flags & DIE_ON_ERROR)
 217                         xfunc_die();
 218                 goto ret;
 219         }
 220         used_res = result;
 221 #if ENABLE_FEATURE_PREFER_IPV4_ADDRESS
 222         while (1) {
 223                 if (used_res->ai_family == AF_INET)
 224                         break;
 225                 used_res = used_res->ai_next;
 226                 if (!used_res) {
 227                         used_res = result;
 228                         break;
 229                 }
 230         }
 231 #endif
 232         r = xmalloc(offsetof(len_and_sockaddr, u.sa) + used_res->ai_addrlen);
 233         r->len = used_res->ai_addrlen;
 234         memcpy(&r->u.sa, used_res->ai_addr, used_res->ai_addrlen);
 235         set_nport(r, htons(port));
 236  ret:
 237         freeaddrinfo(result);
 238         return r;
 239 }
 240 #if !ENABLE_FEATURE_IPV6
 241 #define str2sockaddr(host, port, af, ai_flags) str2sockaddr(host, port, ai_flags)
 242 #endif
 243
 244 #if ENABLE_FEATURE_IPV6
 245 len_and_sockaddr* FAST_FUNC host_and_af2sockaddr(const char *host, int port, sa_family_t af)
 246 {
 247         return str2sockaddr(host, port, af, 0);
 248 }
 249
 250 len_and_sockaddr* FAST_FUNC xhost_and_af2sockaddr(const char *host, int port, sa_family_t af)
 251 {
 252         return str2sockaddr(host, port, af, DIE_ON_ERROR);
 253 }
 254 #endif
 255
 256 len_and_sockaddr* FAST_FUNC host2sockaddr(const char *host, int port)
 257 {
 258         return str2sockaddr(host, port, AF_UNSPEC, 0);
 259 }
 260
 261 len_and_sockaddr* FAST_FUNC xhost2sockaddr(const char *host, int port)
 262 {
 263         return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
 264 }
 265
 266 len_and_sockaddr* FAST_FUNC xdotted2sockaddr(const char *host, int port)
 267 {
 268         return str2sockaddr(host, port, AF_UNSPEC, AI_NUMERICHOST | DIE_ON_ERROR);
 269 }
 270
 271 #undef xsocket_type
 272 int FAST_FUNC xsocket_type(len_and_sockaddr **lsap, USE_FEATURE_IPV6(int family,) int sock_type)
 273 {
 274         SKIP_FEATURE_IPV6(enum { family = AF_INET };)
 275         len_and_sockaddr *lsa;
 276         int fd;
 277         int len;
 278
 279 #if ENABLE_FEATURE_IPV6
 280         if (family == AF_UNSPEC) {
 281                 fd = socket(AF_INET6, sock_type, 0);
 282                 if (fd >= 0) {
 283                         family = AF_INET6;
 284                         goto done;
 285                 }
 286                 family = AF_INET;
 287         }
 288 #endif
 289         fd = xsocket(family, sock_type, 0);
 290         len = sizeof(struct sockaddr_in);
 291 #if ENABLE_FEATURE_IPV6
 292         if (family == AF_INET6) {
 293  done:
 294                 len = sizeof(struct sockaddr_in6);
 295         }
 296 #endif
 297         lsa = xzalloc(offsetof(len_and_sockaddr, u.sa) + len);
 298         lsa->len = len;
 299         lsa->u.sa.sa_family = family;
 300         *lsap = lsa;
 301         return fd;
 302 }
 303
 304 int FAST_FUNC xsocket_stream(len_and_sockaddr **lsap)
 305 {
 306         return xsocket_type(lsap, USE_FEATURE_IPV6(AF_UNSPEC,) SOCK_STREAM);
 307 }
 308
 309 static int create_and_bind_or_die(const char *bindaddr, int port, int sock_type)
 310 {
 311         int fd;
 312         len_and_sockaddr *lsa;
 313
 314         if (bindaddr && bindaddr[0]) {
 315                 lsa = xdotted2sockaddr(bindaddr, port);
 316                 /* user specified bind addr dictates family */
 317                 fd = xsocket(lsa->u.sa.sa_family, sock_type, 0);
 318         } else {
 319                 fd = xsocket_type(&lsa, USE_FEATURE_IPV6(AF_UNSPEC,) sock_type);
 320                 set_nport(lsa, htons(port));
 321         }
 322         setsockopt_reuseaddr(fd);
 323         xbind(fd, &lsa->u.sa, lsa->len);
 324         free(lsa);
 325         return fd;
 326 }
 327
 328 int FAST_FUNC create_and_bind_stream_or_die(const char *bindaddr, int port)
 329 {
 330         return create_and_bind_or_die(bindaddr, port, SOCK_STREAM);
 331 }
 332
 333 int FAST_FUNC create_and_bind_dgram_or_die(const char *bindaddr, int port)
 334 {
 335         return create_and_bind_or_die(bindaddr, port, SOCK_DGRAM);
 336 }
 337
 338
 339 int FAST_FUNC create_and_connect_stream_or_die(const char *peer, int port)
 340 {
 341         int fd;
 342         len_and_sockaddr *lsa;
 343
 344         lsa = xhost2sockaddr(peer, port);
 345         fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
 346         setsockopt_reuseaddr(fd);
 347         xconnect(fd, &lsa->u.sa, lsa->len);
 348         free(lsa);
 349         return fd;
 350 }
 351
 352 int FAST_FUNC xconnect_stream(const len_and_sockaddr *lsa)
 353 {
 354         int fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
 355         xconnect(fd, &lsa->u.sa, lsa->len);
 356         return fd;
 357 }
 358
 359 /* We hijack this constant to mean something else */
 360 /* It doesn't hurt because we will add this bit anyway */
 361 #define IGNORE_PORT NI_NUMERICSERV
 362 static char* FAST_FUNC sockaddr2str(const struct sockaddr *sa, int flags)
 363 {
 364         char host[128];
 365         char serv[16];
 366         int rc;
 367         socklen_t salen;
 368
 369         salen = LSA_SIZEOF_SA;
 370 #if ENABLE_FEATURE_IPV6
 371         if (sa->sa_family == AF_INET)
 372                 salen = sizeof(struct sockaddr_in);
 373         if (sa->sa_family == AF_INET6)
 374                 salen = sizeof(struct sockaddr_in6);
 375 #endif
 376         rc = getnameinfo(sa, salen,
 377                         host, sizeof(host),
 378         /* can do ((flags & IGNORE_PORT) ? NULL : serv) but why bother? */
 379                         serv, sizeof(serv),
 380                         /* do not resolve port# into service _name_ */
 381                         flags | NI_NUMERICSERV
 382         );
 383         if (rc)
 384                 return NULL;
 385         if (flags & IGNORE_PORT)
 386                 return xstrdup(host);
 387 #if ENABLE_FEATURE_IPV6
 388         if (sa->sa_family == AF_INET6) {
 389                 if (strchr(host, ':')) /* heh, it's not a resolved hostname */
 390                         return xasprintf("[%s]:%s", host, serv);
 391                 /*return xasprintf("%s:%s", host, serv);*/
 392                 /* - fall through instead */
 393         }
 394 #endif
 395         /* For now we don't support anything else, so it has to be INET */
 396         /*if (sa->sa_family == AF_INET)*/
 397                 return xasprintf("%s:%s", host, serv);
 398         /*return xstrdup(host);*/
 399 }
 400
 401 char* FAST_FUNC xmalloc_sockaddr2host(const struct sockaddr *sa)
 402 {
 403         return sockaddr2str(sa, 0);
 404 }
 405
 406 char* FAST_FUNC xmalloc_sockaddr2host_noport(const struct sockaddr *sa)
 407 {
 408         return sockaddr2str(sa, IGNORE_PORT);
 409 }
 410
 411 char* FAST_FUNC xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa)
 412 {
 413         return sockaddr2str(sa, NI_NAMEREQD | IGNORE_PORT);
 414 }
 415 char* FAST_FUNC xmalloc_sockaddr2dotted(const struct sockaddr *sa)
 416 {
 417         return sockaddr2str(sa, NI_NUMERICHOST);
 418 }
 419
 420 char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
 421 {
 422         return sockaddr2str(sa, NI_NUMERICHOST | IGNORE_PORT);
 423 }