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 tarball for details.
   8 */
   9
  10#include <netinet/in.h>
  11#include <net/if.h>
  12#include "libbb.h"
  13
  14void FAST_FUNC setsockopt_reuseaddr(int fd)
  15{
  16        setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &const_int_1, sizeof(const_int_1));
  17}
  18int FAST_FUNC setsockopt_broadcast(int fd)
  19{
  20        return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &const_int_1, sizeof(const_int_1));
  21}
  22int 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
  38len_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
  52void 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 */
  70unsigned 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/*
  95void 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
 106int 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
 117int 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
 131void 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 # */
 152static len_and_sockaddr* str2sockaddr(
 153                const char *host, int port,
 154USE_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
 245len_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
 250len_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
 256len_and_sockaddr* FAST_FUNC host2sockaddr(const char *host, int port)
 257{
 258        return str2sockaddr(host, port, AF_UNSPEC, 0);
 259}
 260
 261len_and_sockaddr* FAST_FUNC xhost2sockaddr(const char *host, int port)
 262{
 263        return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
 264}
 265
 266len_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
 272int 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
 304int FAST_FUNC xsocket_stream(len_and_sockaddr **lsap)
 305{
 306        return xsocket_type(lsap, USE_FEATURE_IPV6(AF_UNSPEC,) SOCK_STREAM);
 307}
 308
 309static 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
 328int 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
 333int 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
 339int 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
 352int 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
 362static 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
 401char* FAST_FUNC xmalloc_sockaddr2host(const struct sockaddr *sa)
 402{
 403        return sockaddr2str(sa, 0);
 404}
 405
 406char* FAST_FUNC xmalloc_sockaddr2host_noport(const struct sockaddr *sa)
 407{
 408        return sockaddr2str(sa, IGNORE_PORT);
 409}
 410
 411char* FAST_FUNC xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa)
 412{
 413        return sockaddr2str(sa, NI_NAMEREQD | IGNORE_PORT);
 414}
 415char* FAST_FUNC xmalloc_sockaddr2dotted(const struct sockaddr *sa)
 416{
 417        return sockaddr2str(sa, NI_NUMERICHOST);
 418}
 419
 420char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
 421{
 422        return sockaddr2str(sa, NI_NUMERICHOST | IGNORE_PORT);
 423}
 424