LXR 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
  17int FAST_FUNC setsockopt_int(int fd, int level, int optname, int optval)
  18{
  19        return setsockopt(fd, level, optname, &optval, sizeof(int));
  20}
  21int FAST_FUNC setsockopt_1(int fd, int level, int optname)
  22{
  23        return setsockopt_int(fd, level, optname, 1);
  24}
  25int FAST_FUNC setsockopt_SOL_SOCKET_int(int fd, int optname, int optval)
  26{
  27        return setsockopt_int(fd, SOL_SOCKET, optname, optval);
  28}
  29int FAST_FUNC setsockopt_SOL_SOCKET_1(int fd, int optname)
  30{
  31        return setsockopt_SOL_SOCKET_int(fd, optname, 1);
  32}
  33
  34void FAST_FUNC setsockopt_reuseaddr(int fd)
  35{
  36        setsockopt_SOL_SOCKET_1(fd, SO_REUSEADDR);
  37}
  38int FAST_FUNC setsockopt_broadcast(int fd)
  39{
  40        return setsockopt_SOL_SOCKET_1(fd, SO_BROADCAST);
  41}
  42int FAST_FUNC setsockopt_keepalive(int fd)
  43{
  44        return setsockopt_SOL_SOCKET_1(fd, SO_KEEPALIVE);
  45}
  46
  47#ifdef SO_BINDTODEVICE
  48int 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
  64int 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
  72static 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
  91len_and_sockaddr* FAST_FUNC get_sock_lsa(int fd)
  92{
  93        return get_lsa(fd, getsockname);
  94}
  95
  96len_and_sockaddr* FAST_FUNC get_peer_lsa(int fd)
  97{
  98        return get_lsa(fd, getpeername);
  99}
 100
 101void 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 */
 119unsigned 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
 144int 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
 158void 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 # */
 181static len_and_sockaddr* str2sockaddr(
 182                const char *host, int port,
 183IF_FEATURE_IPV6(sa_family_t af,)
 184                int ai_flags)
 185{
 186IF_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
 320len_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
 325len_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
 331len_and_sockaddr* FAST_FUNC host2sockaddr(const char *host, int port)
 332{
 333        return str2sockaddr(host, port, AF_UNSPEC, 0);
 334}
 335
 336len_and_sockaddr* FAST_FUNC xhost2sockaddr(const char *host, int port)
 337{
 338        return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
 339}
 340
 341len_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
 346int 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
 381int FAST_FUNC xsocket_stream(len_and_sockaddr **lsap)
 382{
 383        return xsocket_type(lsap, AF_UNSPEC, SOCK_STREAM);
 384}
 385
 386static 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
 405int 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
 410int 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
 416int 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
 429int 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
 439static 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
 485char* FAST_FUNC xmalloc_sockaddr2host(const struct sockaddr *sa)
 486{
 487        return sockaddr2str(sa, 0);
 488}
 489
 490char* FAST_FUNC xmalloc_sockaddr2host_noport(const struct sockaddr *sa)
 491{
 492        return sockaddr2str(sa, IGNORE_PORT);
 493}
 494
 495char* FAST_FUNC xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa)
 496{
 497        return sockaddr2str(sa, NI_NAMEREQD | IGNORE_PORT);
 498}
 499char* FAST_FUNC xmalloc_sockaddr2dotted(const struct sockaddr *sa)
 500{
 501        return sockaddr2str(sa, NI_NUMERICHOST);
 502}
 503
 504char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
 505{
 506        return sockaddr2str(sa, NI_NUMERICHOST | IGNORE_PORT);
 507}
 508