---

getaddrinfo.c

Go to the documentation of this file.

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 *
 * Changes Copyright (C) 2001 by Martin Pool <mbp@samba.org>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * "#ifdef FAITH" part is local hack for supporting IPv4-v6 translator.
 *
 * Issues to be discussed:
 * - Thread safe-ness must be checked.
 * - Return values.  There are nonstandard return values defined and used
 *   in the source code.  This is because RFC2133 is silent about which error
 *   code must be returned for which situation.
 * - PF_UNSPEC case would be handled in getipnodebyname() with the AI_ALL flag.
 */

#include <rsync.h>

#if defined(__KAME__) && defined(INET6)
# define FAITH
#endif

#define SUCCESS 0
#define ANY 0
#define YES 1
#define NO  0

#ifdef FAITH
static int translate = NO;
static struct in6_addr faith_prefix = IN6ADDR_ANY_INIT;
#endif /* FAITH */

/* Amdahl's UTS 2.1.2 defines NO_ADDRESS instead of NO_DATA. */

#ifndef NO_DATA
#ifdef NO_ADDRESS
#define NO_DATA NO_ADDRESS
#endif
#endif /* ndef NO_DATA */

static const char in_addrany[] = { 0, 0, 0, 0 };
static const char in6_addrany[] = {
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static const char in_loopback[] = { 127, 0, 0, 1 }; 
static const char in6_loopback[] = {
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
};

struct sockinet {
        u_char  si_len;
        u_char  si_family;
        u_short si_port;
};

static struct afd {
        int a_af;
        int a_addrlen;
        int a_socklen;
        int a_off;
        const char *a_addrany;
        const char *a_loopback; 
} afdl [] = {
#ifdef INET6
#define N_INET6 0
        {PF_INET6, sizeof(struct in6_addr),
         sizeof(struct sockaddr_in6),
         offsetof(struct sockaddr_in6, sin6_addr),
         in6_addrany, in6_loopback},
#define N_INET  1
#else
#define N_INET  0
#endif
        {PF_INET, sizeof(struct in_addr),
         sizeof(struct sockaddr_in),
         offsetof(struct sockaddr_in, sin_addr),
         in_addrany, in_loopback},
        {0, 0, 0, 0, NULL, NULL},
};

#ifdef INET6
#define PTON_MAX        16
#else
#define PTON_MAX        4
#endif


static int get_name (const char *, struct afd *,
                     struct addrinfo **, char *, struct addrinfo *,
                     int);
static int get_addr (const char *, int, struct addrinfo **,
                        struct addrinfo *, int);
static int str_isnumber (const char *);
        
static char *ai_errlist[] = {
        "success.",
        "address family for hostname not supported.",   /* EAI_ADDRFAMILY */
        "temporary failure in name resolution.",        /* EAI_AGAIN      */
        "invalid value for ai_flags.",                  /* EAI_BADFLAGS   */
        "non-recoverable failure in name resolution.",  /* EAI_FAIL       */
        "ai_family not supported.",                     /* EAI_FAMILY     */
        "memory allocation failure.",                   /* EAI_MEMORY     */
        "no address associated with hostname.",         /* EAI_NODATA     */
        "hostname nor servname provided, or not known.",/* EAI_NONAME     */
        "servname not supported for ai_socktype.",      /* EAI_SERVICE    */
        "ai_socktype not supported.",                   /* EAI_SOCKTYPE   */
        "system error returned in errno.",              /* EAI_SYSTEM     */
        "invalid value for hints.",                     /* EAI_BADHINTS   */
        "resolved protocol is unknown.",                /* EAI_PROTOCOL   */
        "unknown error.",                               /* EAI_MAX        */
};

#define GET_CANONNAME(ai, str) \
if (pai->ai_flags & AI_CANONNAME) {\
        if (((ai)->ai_canonname = (char *)malloc(strlen(str) + 1)) != NULL) {\
                strcpy((ai)->ai_canonname, (str));\
        } else {\
                error = EAI_MEMORY;\
                goto free;\
        }\
}


static int get_ai(struct addrinfo ** to_ai,
                   struct addrinfo const * pai,
                   struct afd *afd,
                   const char *addr,
                   short port)
{
        char *p;
        if ((*to_ai = (struct addrinfo *)malloc(sizeof(struct addrinfo) +
                                              ((afd)->a_socklen)))
            == NULL) 
                return 0;
        memcpy(*to_ai, pai, sizeof(struct addrinfo));
        (*to_ai)->ai_addr = (struct sockaddr *)((*to_ai) + 1);
        memset((*to_ai)->ai_addr, 0, (afd)->a_socklen);
        (*to_ai)->ai_addrlen = (afd)->a_socklen;
#if HAVE_SOCKADDR_LEN
        (*to_ai)->ai_addr->sa_len= (afd)->a_socklen;
#endif
        (*to_ai)->ai_addr->sa_family = (*to_ai)->ai_family = (afd)->a_af;
        ((struct sockinet *)(*to_ai)->ai_addr)->si_port = port;
        p = (char *)((*to_ai)->ai_addr);
        memcpy(p + (afd)->a_off, (addr), (afd)->a_addrlen);
        return 1;
}

#define ERR(err) { error = (err); goto bad; }

char *
gai_strerror(ecode)
        int ecode;
{
        if (ecode < 0 || ecode > EAI_MAX)
                ecode = EAI_MAX;
        return ai_errlist[ecode];
}

void
freeaddrinfo(ai)
        struct addrinfo *ai;
{
        struct addrinfo *next;

        do {
                next = ai->ai_next;
                if (ai->ai_canonname)
                        free(ai->ai_canonname);
                /* no need to free(ai->ai_addr) */
                free(ai);
        } while ((ai = next) != NULL);
}

static int
str_isnumber(p)
        const char *p;
{
        char *q = (char *)p;
        while (*q) {
                if (! isdigit(*q))
                        return NO;
                q++;
        }
        return YES;
}

int
getaddrinfo(hostname, servname, hints, res)
        const char *hostname, *servname;
        const struct addrinfo *hints;
        struct addrinfo **res;
{
        struct addrinfo sentinel;
        struct addrinfo *top = NULL;
        struct addrinfo *cur;
        int i, error = 0;
        char pton[PTON_MAX];
        struct addrinfo ai;
        struct addrinfo *pai;
        u_short port;

#ifdef FAITH
        static int firsttime = 1;

        if (firsttime) {
                /* translator hack */
                {
                        char *q = getenv("GAI");
                        if (q && inet_pton(AF_INET6, q, &faith_prefix) == 1)
                                translate = YES;
                }
                firsttime = 0;
        }
#endif

        /* initialize file static vars */
        sentinel.ai_next = NULL;
        cur = &sentinel;
        pai = &ai;
        pai->ai_flags = 0;
        pai->ai_family = PF_UNSPEC;
        pai->ai_socktype = ANY;
        pai->ai_protocol = ANY;
        pai->ai_addrlen = 0;
        pai->ai_canonname = NULL;
        pai->ai_addr = NULL;
        pai->ai_next = NULL;
        port = ANY;
        
        if (hostname == NULL && servname == NULL)
                return EAI_NONAME;
        if (hints) {
                /* error check for hints */
                if (hints->ai_addrlen || hints->ai_canonname ||
                    hints->ai_addr || hints->ai_next)
                        ERR(EAI_BADHINTS); /* xxx */
                if (hints->ai_flags & ~AI_MASK)
                        ERR(EAI_BADFLAGS);
                switch (hints->ai_family) {
                case PF_UNSPEC:
                case PF_INET:
#ifdef INET6
                case PF_INET6:
#endif
                        break;
                default:
                        ERR(EAI_FAMILY);
                }
                memcpy(pai, hints, sizeof(*pai));
                switch (pai->ai_socktype) {
                case ANY:
                        switch (pai->ai_protocol) {
                        case ANY:
                                break;
                        case IPPROTO_UDP:
                                pai->ai_socktype = SOCK_DGRAM;
                                break;
                        case IPPROTO_TCP:
                                pai->ai_socktype = SOCK_STREAM;
                                break;
                        default:
                                pai->ai_socktype = SOCK_RAW;
                                break;
                        }
                        break;
                case SOCK_RAW:
                        break;
                case SOCK_DGRAM:
                        if (pai->ai_protocol != IPPROTO_UDP &&
                            pai->ai_protocol != ANY)
                                ERR(EAI_BADHINTS);      /*xxx*/
                        pai->ai_protocol = IPPROTO_UDP;
                        break;
                case SOCK_STREAM:
                        if (pai->ai_protocol != IPPROTO_TCP &&
                            pai->ai_protocol != ANY)
                                ERR(EAI_BADHINTS);      /*xxx*/
                        pai->ai_protocol = IPPROTO_TCP;
                        break;
                default:
                        ERR(EAI_SOCKTYPE);
                        break;
                }
        }

        /*
         * service port
         */
        if (servname) {
                if (str_isnumber(servname)) {
                        if (pai->ai_socktype == ANY) {
                                /* caller accept *ANY* socktype */
                                pai->ai_socktype = SOCK_DGRAM;
                                pai->ai_protocol = IPPROTO_UDP;
                        }
                        port = htons(atoi(servname));
                } else {
                        struct servent *sp;
                        char *proto;

                        proto = NULL;
                        switch (pai->ai_socktype) {
                        case ANY:
                                proto = NULL;
                                break;
                        case SOCK_DGRAM:
                                proto = "udp";
                                break;
                        case SOCK_STREAM:
                                proto = "tcp";
                                break;
                        default:
                                fprintf(stderr, "panic!\n");
                                break;
                        }
                        if ((sp = getservbyname(servname, proto)) == NULL)
                                ERR(EAI_SERVICE);
                        port = sp->s_port;
                        if (pai->ai_socktype == ANY) {
                                if (strcmp(sp->s_proto, "udp") == 0) {
                                        pai->ai_socktype = SOCK_DGRAM;
                                        pai->ai_protocol = IPPROTO_UDP;
                                } else if (strcmp(sp->s_proto, "tcp") == 0) {
                                        pai->ai_socktype = SOCK_STREAM;
                                        pai->ai_protocol = IPPROTO_TCP;
                                } else
                                        ERR(EAI_PROTOCOL);      /*xxx*/
                        }
                }
        }
        
        /*
         * hostname == NULL.
         * passive socket -> anyaddr (0.0.0.0 or ::)
         * non-passive socket -> localhost (127.0.0.1 or ::1)
         */
        if (hostname == NULL) {
                struct afd *afd;

                for (afd = &afdl[0]; afd->a_af; afd++) {
                        if (!(pai->ai_family == PF_UNSPEC
                           || pai->ai_family == afd->a_af)) {
                                continue;
                        }

                        if (pai->ai_flags & AI_PASSIVE) {
                                if (!get_ai(&cur->ai_next, pai, afd, afd->a_addrany, port))
                                        goto free;
                                /* xxx meaningless?
                                 * GET_CANONNAME(cur->ai_next, "anyaddr");
                                 */
                        } else {
                                if (!get_ai(&cur->ai_next, pai, afd, afd->a_loopback,
                                        port))
                                        goto free;
                                /* xxx meaningless?
                                 * GET_CANONNAME(cur->ai_next, "localhost");
                                 */
                        }
                        cur = cur->ai_next;
                }
                top = sentinel.ai_next;
                if (top)
                        goto good;
                else
                        ERR(EAI_FAMILY);
        }
        
        /* hostname as numeric name */
        for (i = 0; afdl[i].a_af; i++) {
                if (inet_pton(afdl[i].a_af, hostname, pton)) {
                        u_long v4a;

                        switch (afdl[i].a_af) {
                        case AF_INET:
                                v4a = ((struct in_addr *)pton)->s_addr;
                                if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
                                        pai->ai_flags &= ~AI_CANONNAME;
                                v4a >>= IN_CLASSA_NSHIFT;
                                if (v4a == 0 || v4a == IN_LOOPBACKNET)
                                        pai->ai_flags &= ~AI_CANONNAME;
                                break;
#ifdef INET6
                        case AF_INET6:
                        {
                                u_char pfx;
                                pfx = ((struct in6_addr *)pton)->s6_addr[0];
                                if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
                                        pai->ai_flags &= ~AI_CANONNAME;
                                break;
                        }
#endif
                        }
                        
                        if (pai->ai_family == afdl[i].a_af ||
                            pai->ai_family == PF_UNSPEC) {
                                if (! (pai->ai_flags & AI_CANONNAME)) {
                                        if (get_ai(&top, pai, &afdl[i], pton, port))
                                                goto good;
                                        else
                                                goto free;
                                }
                                /*
                                 * if AI_CANONNAME and if reverse lookup
                                 * fail, return ai anyway to pacify
                                 * calling application.
                                 *
                                 * XXX getaddrinfo() is a name->address
                                 * translation function, and it looks strange
                                 * that we do addr->name translation here.
                                 */
                                get_name(pton, &afdl[i], &top, pton, pai, port);
                                goto good;
                        } else 
                                ERR(EAI_FAMILY);        /*xxx*/
                }
        }

        if (pai->ai_flags & AI_NUMERICHOST)
                ERR(EAI_NONAME);

        /* hostname as alphabetical name */
        error = get_addr(hostname, pai->ai_family, &top, pai, port);
        if (error == 0) {
                if (top) {
 good:
                        *res = top;
                        return SUCCESS;
                } else
                        error = EAI_FAIL;
        }
 free:
        if (top)
                freeaddrinfo(top);
 bad:
        *res = NULL;
        return error;
}

static int
get_name(addr, afd, res, numaddr, pai, port0)
        const char *addr;
        struct afd *afd;
        struct addrinfo **res;
        char *numaddr;
        struct addrinfo *pai;
        int port0;
{
        u_short port = port0 & 0xffff;
        struct hostent *hp;
        struct addrinfo *cur;
        int error = 0;
        
#ifdef INET6
        {
                int h_error;
                hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
        }
#else
        hp = gethostbyaddr(addr, afd->a_addrlen, AF_INET);
#endif
        if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
                if (!get_ai(&cur, pai, afd, hp->h_addr_list[0], port))
                        goto free;
                GET_CANONNAME(cur, hp->h_name);
        } else {
                if (!get_ai(&cur, pai, afd, numaddr, port))
                        goto free;
        }
        
#ifdef INET6
        if (hp)
                freehostent(hp);
#endif
        *res = cur;
        return SUCCESS;
 free:
        if (cur)
                freeaddrinfo(cur);
#ifdef INET6
        if (hp)
                freehostent(hp);
#endif
 /* bad: */
        *res = NULL;
        return error;
}

static int
get_addr(hostname, af, res, pai, port0)
        const char *hostname;
        int af;
        struct addrinfo **res;
        struct addrinfo *pai;
        int port0;
{
        u_short port = port0 & 0xffff;
        struct addrinfo sentinel;
        struct hostent *hp;
        struct addrinfo *top, *cur;
        struct afd *afd;
        int i, error = 0, h_error;
        char *ap;
#ifndef INET6
        extern int h_errno;
#endif

        top = NULL;
        sentinel.ai_next = NULL;
        cur = &sentinel;
#ifdef INET6
        if (af == AF_UNSPEC) {
                hp = getipnodebyname(hostname, AF_INET6,
                                AI_ADDRCONFIG|AI_ALL|AI_V4MAPPED, &h_error);
        } else
                hp = getipnodebyname(hostname, af, AI_ADDRCONFIG, &h_error);
#else
        hp = gethostbyname(hostname);
        h_error = h_errno;
#endif
        if (hp == NULL) {
                switch (h_error) {
                case HOST_NOT_FOUND:
                case NO_DATA:
                        error = EAI_NODATA;
                        break;
                case TRY_AGAIN:
                        error = EAI_AGAIN;
                        break;
                case NO_RECOVERY:
                default:
                        error = EAI_FAIL;
                        break;
                }
                goto bad;
        }

        if ((hp->h_name == NULL) || (hp->h_name[0] == 0) ||
            (hp->h_addr_list[0] == NULL))
                ERR(EAI_FAIL);
        
        for (i = 0; (ap = hp->h_addr_list[i]) != NULL; i++) {
                switch (af) {
#ifdef INET6
                case AF_INET6:
                        afd = &afdl[N_INET6];
                        break;
#endif
#ifndef INET6
                default:        /* AF_UNSPEC */
#endif
                case AF_INET:
                        afd = &afdl[N_INET];
                        break;
#ifdef INET6
                default:        /* AF_UNSPEC */
                        if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
                                ap += sizeof(struct in6_addr) -
                                        sizeof(struct in_addr);
                                afd = &afdl[N_INET];
                        } else
                                afd = &afdl[N_INET6];
                        break;
#endif
                }
#ifdef FAITH
                if (translate && afd->a_af == AF_INET) {
                        struct in6_addr *in6;

                        if (!get_ai(&cur->ai_next, pai, &afdl[N_INET6], ap, port))
                                goto free;
                        in6 = &((struct sockaddr_in6 *)cur->ai_next->ai_addr)->sin6_addr;
                        memcpy(&in6->s6_addr32[0], &faith_prefix,
                            sizeof(struct in6_addr) - sizeof(struct in_addr));
                        memcpy(&in6->s6_addr32[3], ap, sizeof(struct in_addr));
                } else
#endif /* FAITH */
                if (!get_ai(&cur->ai_next, pai, afd, ap, port))
                        goto free;
                if (cur == &sentinel) {
                        top = cur->ai_next;
                        GET_CANONNAME(top, hp->h_name);
                }
                cur = cur->ai_next;
        }
#ifdef INET6
        freehostent(hp);
#endif
        *res = top;
        return SUCCESS;
 free:
        if (top)
                freeaddrinfo(top);
#ifdef INET6
        if (hp)
                freehostent(hp);
#endif
 bad:
        *res = NULL;
        return error;
}

---