source: MondoRescue/branches/3.0/mindi-busybox/libbb/xconnect.c@ 2899

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Connect to host at port using address resolution from getaddrinfo
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

#include <sys/types.h>
#include <sys/socket.h> /* netinet/in.h needs it */
#include <netinet/in.h>
#include <net/if.h>
#include <sys/un.h>
#include "libbb.h"

void FAST_FUNC setsockopt_reuseaddr(int fd)
{
    setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &const_int_1, sizeof(const_int_1));
}
int FAST_FUNC setsockopt_broadcast(int fd)
{
    return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &const_int_1, sizeof(const_int_1));
}

#ifdef SO_BINDTODEVICE
int FAST_FUNC setsockopt_bindtodevice(int fd, const char *iface)
{
    int r;
    struct ifreq ifr;
    strncpy_IFNAMSIZ(ifr.ifr_name, iface);
    /* NB: passing (iface, strlen(iface) + 1) does not work!
     * (maybe it works on _some_ kernels, but not on 2.6.26)
     * Actually, ifr_name is at offset 0, and in practice
     * just giving char[IFNAMSIZ] instead of struct ifreq works too.
     * But just in case it's not true on some obscure arch... */
    r = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
    if (r)
        bb_perror_msg("can't bind to interface %s", iface);
    return r;
}
#else
int FAST_FUNC setsockopt_bindtodevice(int fd UNUSED_PARAM,
        const char *iface UNUSED_PARAM)
{
    bb_error_msg("SO_BINDTODEVICE is not supported on this system");
    return -1;
}
#endif

static len_and_sockaddr* get_lsa(int fd, int (*get_name)(int fd, struct sockaddr *addr, socklen_t *addrlen))
{
    len_and_sockaddr lsa;
    len_and_sockaddr *lsa_ptr;

    lsa.len = LSA_SIZEOF_SA;
    if (get_name(fd, &lsa.u.sa, &lsa.len) != 0)
        return NULL;

    lsa_ptr = xzalloc(LSA_LEN_SIZE + lsa.len);
    if (lsa.len > LSA_SIZEOF_SA) { /* rarely (if ever) happens */
        lsa_ptr->len = lsa.len;
        get_name(fd, &lsa_ptr->u.sa, &lsa_ptr->len);
    } else {
        memcpy(lsa_ptr, &lsa, LSA_LEN_SIZE + lsa.len);
    }
    return lsa_ptr;
}

len_and_sockaddr* FAST_FUNC get_sock_lsa(int fd)
{
    return get_lsa(fd, getsockname);
}

len_and_sockaddr* FAST_FUNC get_peer_lsa(int fd)
{
    return get_lsa(fd, getpeername);
}

void FAST_FUNC xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
{
    if (connect(s, s_addr, addrlen) < 0) {
        if (ENABLE_FEATURE_CLEAN_UP)
            close(s);
        if (s_addr->sa_family == AF_INET)
            bb_perror_msg_and_die("%s (%s)",
                "can't connect to remote host",
                inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
        bb_perror_msg_and_die("can't connect to remote host");
    }
}

/* Return port number for a service.
 * If "port" is a number use it as the port.
 * If "port" is a name it is looked up in /etc/services,
 * if it isnt found return default_port
 */
unsigned FAST_FUNC bb_lookup_port(const char *port, const char *protocol, unsigned default_port)
{
    unsigned port_nr = default_port;
    if (port) {
        int old_errno;

        /* Since this is a lib function, we're not allowed to reset errno to 0.
         * Doing so could break an app that is deferring checking of errno. */
        old_errno = errno;
        port_nr = bb_strtou(port, NULL, 10);
        if (errno || port_nr > 65535) {
            struct servent *tserv = getservbyname(port, protocol);
            port_nr = default_port;
            if (tserv)
                port_nr = ntohs(tserv->s_port);
        }
        errno = old_errno;
    }
    return (uint16_t)port_nr;
}


/* "New" networking API */


int FAST_FUNC get_nport(const struct sockaddr *sa)
{
#if ENABLE_FEATURE_IPV6
    if (sa->sa_family == AF_INET6) {
        return ((struct sockaddr_in6*)sa)->sin6_port;
    }
#endif
    if (sa->sa_family == AF_INET) {
        return ((struct sockaddr_in*)sa)->sin_port;
    }
    /* What? UNIX socket? IPX?? :) */
    return -1;
}

void FAST_FUNC set_nport(len_and_sockaddr *lsa, unsigned port)
{
#if ENABLE_FEATURE_IPV6
    if (lsa->u.sa.sa_family == AF_INET6) {
        lsa->u.sin6.sin6_port = port;
        return;
    }
#endif
    if (lsa->u.sa.sa_family == AF_INET) {
        lsa->u.sin.sin_port = port;
        return;
    }
    /* What? UNIX socket? IPX?? :) */
}

/* We hijack this constant to mean something else */
/* It doesn't hurt because we will remove this bit anyway */
#define DIE_ON_ERROR AI_CANONNAME

/* host: "1.2.3.4[:port]", "www.google.com[:port]"
 * port: if neither of above specifies port # */
static len_and_sockaddr* str2sockaddr(
        const char *host, int port,
IF_FEATURE_IPV6(sa_family_t af,)
        int ai_flags)
{
IF_NOT_FEATURE_IPV6(sa_family_t af = AF_INET;)
    int rc;
    len_and_sockaddr *r;
    struct addrinfo *result = NULL;
    struct addrinfo *used_res;
    const char *org_host = host; /* only for error msg */
    const char *cp;
    struct addrinfo hint;

    if (ENABLE_FEATURE_UNIX_LOCAL && strncmp(host, "local:", 6) == 0) {
        struct sockaddr_un *sun;

        r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_un));
        r->len = sizeof(struct sockaddr_un);
        r->u.sa.sa_family = AF_UNIX;
        sun = (struct sockaddr_un *)&r->u.sa;
        safe_strncpy(sun->sun_path, host + 6, sizeof(sun->sun_path));
        return r;
    }

    r = NULL;

    /* Ugly parsing of host:addr */
    if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
        /* Even uglier parsing of [xx]:nn */
        host++;
        cp = strchr(host, ']');
        if (!cp || (cp[1] != ':' && cp[1] != '\0')) {
            /* Malformed: must be [xx]:nn or [xx] */
            bb_error_msg("bad address '%s'", org_host);
            if (ai_flags & DIE_ON_ERROR)
                xfunc_die();
            return NULL;
        }
    } else {
        cp = strrchr(host, ':');
        if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
            /* There is more than one ':' (e.g. "::1") */
            cp = NULL; /* it's not a port spec */
        }
    }
    if (cp) { /* points to ":" or "]:" */
        int sz = cp - host + 1;

        host = safe_strncpy(alloca(sz), host, sz);
        if (ENABLE_FEATURE_IPV6 && *cp != ':') {
            cp++; /* skip ']' */
            if (*cp == '\0') /* [xx] without port */
                goto skip;
        }
        cp++; /* skip ':' */
        port = bb_strtou(cp, NULL, 10);
        if (errno || (unsigned)port > 0xffff) {
            bb_error_msg("bad port spec '%s'", org_host);
            if (ai_flags & DIE_ON_ERROR)
                xfunc_die();
            return NULL;
        }
 skip: ;
    }

    /* Next two if blocks allow to skip getaddrinfo()
     * in case host name is a numeric IP(v6) address.
     * getaddrinfo() initializes DNS resolution machinery,
     * scans network config and such - tens of syscalls.
     */
    /* If we were not asked specifically for IPv6,
     * check whether this is a numeric IPv4 */
    IF_FEATURE_IPV6(if(af != AF_INET6)) {
        struct in_addr in4;
        if (inet_aton(host, &in4) != 0) {
            r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in));
            r->len = sizeof(struct sockaddr_in);
            r->u.sa.sa_family = AF_INET;
            r->u.sin.sin_addr = in4;
            goto set_port;
        }
    }
#if ENABLE_FEATURE_IPV6
    /* If we were not asked specifically for IPv4,
     * check whether this is a numeric IPv6 */
    if (af != AF_INET) {
        struct in6_addr in6;
        if (inet_pton(AF_INET6, host, &in6) > 0) {
            r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in6));
            r->len = sizeof(struct sockaddr_in6);
            r->u.sa.sa_family = AF_INET6;
            r->u.sin6.sin6_addr = in6;
            goto set_port;
        }
    }
#endif

    memset(&hint, 0 , sizeof(hint));
    hint.ai_family = af;
    /* Needed. Or else we will get each address thrice (or more)
     * for each possible socket type (tcp,udp,raw...): */
    hint.ai_socktype = SOCK_STREAM;
    hint.ai_flags = ai_flags & ~DIE_ON_ERROR;
    rc = getaddrinfo(host, NULL, &hint, &result);
    if (rc || !result) {
        bb_error_msg("bad address '%s'", org_host);
        if (ai_flags & DIE_ON_ERROR)
            xfunc_die();
        goto ret;
    }
    used_res = result;
#if ENABLE_FEATURE_PREFER_IPV4_ADDRESS
    while (1) {
        if (used_res->ai_family == AF_INET)
            break;
        used_res = used_res->ai_next;
        if (!used_res) {
            used_res = result;
            break;
        }
    }
#endif
    r = xmalloc(LSA_LEN_SIZE + used_res->ai_addrlen);
    r->len = used_res->ai_addrlen;
    memcpy(&r->u.sa, used_res->ai_addr, used_res->ai_addrlen);

 set_port:
    set_nport(r, htons(port));
 ret:
    freeaddrinfo(result);
    return r;
}
#if !ENABLE_FEATURE_IPV6
#define str2sockaddr(host, port, af, ai_flags) str2sockaddr(host, port, ai_flags)
#endif

#if ENABLE_FEATURE_IPV6
len_and_sockaddr* FAST_FUNC host_and_af2sockaddr(const char *host, int port, sa_family_t af)
{
    return str2sockaddr(host, port, af, 0);
}

len_and_sockaddr* FAST_FUNC xhost_and_af2sockaddr(const char *host, int port, sa_family_t af)
{
    return str2sockaddr(host, port, af, DIE_ON_ERROR);
}
#endif

len_and_sockaddr* FAST_FUNC host2sockaddr(const char *host, int port)
{
    return str2sockaddr(host, port, AF_UNSPEC, 0);
}

len_and_sockaddr* FAST_FUNC xhost2sockaddr(const char *host, int port)
{
    return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
}

len_and_sockaddr* FAST_FUNC xdotted2sockaddr(const char *host, int port)
{
    return str2sockaddr(host, port, AF_UNSPEC, AI_NUMERICHOST | DIE_ON_ERROR);
}

#undef xsocket_type
int FAST_FUNC xsocket_type(len_and_sockaddr **lsap, IF_FEATURE_IPV6(int family,) int sock_type)
{
    IF_NOT_FEATURE_IPV6(enum { family = AF_INET };)
    len_and_sockaddr *lsa;
    int fd;
    int len;

#if ENABLE_FEATURE_IPV6
    if (family == AF_UNSPEC) {
        fd = socket(AF_INET6, sock_type, 0);
        if (fd >= 0) {
            family = AF_INET6;
            goto done;
        }
        family = AF_INET;
    }
#endif
    fd = xsocket(family, sock_type, 0);
    len = sizeof(struct sockaddr_in);
#if ENABLE_FEATURE_IPV6
    if (family == AF_INET6) {
 done:
        len = sizeof(struct sockaddr_in6);
    }
#endif
    lsa = xzalloc(LSA_LEN_SIZE + len);
    lsa->len = len;
    lsa->u.sa.sa_family = family;
    *lsap = lsa;
    return fd;
}

int FAST_FUNC xsocket_stream(len_and_sockaddr **lsap)
{
    return xsocket_type(lsap, IF_FEATURE_IPV6(AF_UNSPEC,) SOCK_STREAM);
}

static int create_and_bind_or_die(const char *bindaddr, int port, int sock_type)
{
    int fd;
    len_and_sockaddr *lsa;

    if (bindaddr && bindaddr[0]) {
        lsa = xdotted2sockaddr(bindaddr, port);
        /* user specified bind addr dictates family */
        fd = xsocket(lsa->u.sa.sa_family, sock_type, 0);
    } else {
        fd = xsocket_type(&lsa, IF_FEATURE_IPV6(AF_UNSPEC,) sock_type);
        set_nport(lsa, htons(port));
    }
    setsockopt_reuseaddr(fd);
    xbind(fd, &lsa->u.sa, lsa->len);
    free(lsa);
    return fd;
}

int FAST_FUNC create_and_bind_stream_or_die(const char *bindaddr, int port)
{
    return create_and_bind_or_die(bindaddr, port, SOCK_STREAM);
}

int FAST_FUNC create_and_bind_dgram_or_die(const char *bindaddr, int port)
{
    return create_and_bind_or_die(bindaddr, port, SOCK_DGRAM);
}


int FAST_FUNC create_and_connect_stream_or_die(const char *peer, int port)
{
    int fd;
    len_and_sockaddr *lsa;

    lsa = xhost2sockaddr(peer, port);
    fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
    setsockopt_reuseaddr(fd);
    xconnect(fd, &lsa->u.sa, lsa->len);
    free(lsa);
    return fd;
}

int FAST_FUNC xconnect_stream(const len_and_sockaddr *lsa)
{
    int fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
    xconnect(fd, &lsa->u.sa, lsa->len);
    return fd;
}

/* We hijack this constant to mean something else */
/* It doesn't hurt because we will add this bit anyway */
#define IGNORE_PORT NI_NUMERICSERV
static char* FAST_FUNC sockaddr2str(const struct sockaddr *sa, int flags)
{
    char host[128];
    char serv[16];
    int rc;
    socklen_t salen;

    if (ENABLE_FEATURE_UNIX_LOCAL && sa->sa_family == AF_UNIX) {
        struct sockaddr_un *sun = (struct sockaddr_un *)sa;
        return xasprintf("local:%.*s",
                (int) sizeof(sun->sun_path),
                sun->sun_path);
    }

    salen = LSA_SIZEOF_SA;
#if ENABLE_FEATURE_IPV6
    if (sa->sa_family == AF_INET)
        salen = sizeof(struct sockaddr_in);
    if (sa->sa_family == AF_INET6)
        salen = sizeof(struct sockaddr_in6);
#endif
    rc = getnameinfo(sa, salen,
            host, sizeof(host),
    /* can do ((flags & IGNORE_PORT) ? NULL : serv) but why bother? */
            serv, sizeof(serv),
            /* do not resolve port# into service _name_ */
            flags | NI_NUMERICSERV
    );
    if (rc)
        return NULL;
    if (flags & IGNORE_PORT)
        return xstrdup(host);
#if ENABLE_FEATURE_IPV6
    if (sa->sa_family == AF_INET6) {
        if (strchr(host, ':')) /* heh, it's not a resolved hostname */
            return xasprintf("[%s]:%s", host, serv);
        /*return xasprintf("%s:%s", host, serv);*/
        /* - fall through instead */
    }
#endif
    /* For now we don't support anything else, so it has to be INET */
    /*if (sa->sa_family == AF_INET)*/
        return xasprintf("%s:%s", host, serv);
    /*return xstrdup(host);*/
}

char* FAST_FUNC xmalloc_sockaddr2host(const struct sockaddr *sa)
{
    return sockaddr2str(sa, 0);
}

char* FAST_FUNC xmalloc_sockaddr2host_noport(const struct sockaddr *sa)
{
    return sockaddr2str(sa, IGNORE_PORT);
}

char* FAST_FUNC xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa)
{
    return sockaddr2str(sa, NI_NAMEREQD | IGNORE_PORT);
}
char* FAST_FUNC xmalloc_sockaddr2dotted(const struct sockaddr *sa)
{
    return sockaddr2str(sa, NI_NUMERICHOST);
}

char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
{
    return sockaddr2str(sa, NI_NUMERICHOST | IGNORE_PORT);
}