/* $NetBSD: getnameinfo.c,v 1.43 2006/02/17 15:58:26 ginsbach Exp $ */ /* $KAME: getnameinfo.c,v 1.45 2000/09/25 22:43:56 itojun Exp $ */ /* * Copyright (c) 2000 Ben Harris. * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. * All rights reserved. * * 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. */ /* * Issues to be discussed: * - Thread safe-ness must be checked * - RFC2553 says that we should raise error on short buffer. X/Open says * we need to truncate the result. We obey RFC2553 (and X/Open should be * modified). ipngwg rough consensus seems to follow RFC2553. * - What is "local" in NI_FQDN? * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other. * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if * sin6_scope_id is filled - standardization status? * XXX breaks backward compat for code that expects no scopeid. * beware on merge. */ #include <sys/cdefs.h> #if defined(LIBC_SCCS) && !defined(lint) __RCSID("$NetBSD: getnameinfo.c,v 1.43 2006/02/17 15:58:26 ginsbach Exp $"); #endif /* LIBC_SCCS and not lint */ #include <sys/types.h> #include <sys/socket.h> #include <net/if.h> #include <net/if_dl.h> #include <net/if_ieee1394.h> #include <net/if_types.h> #include <netinet/in.h> #include <arpa/inet.h> #include "arpa_nameser.h" #include <assert.h> #include <limits.h> #include <netdb.h> #ifdef ANDROID_CHANGES #include "resolv_private.h" #include <sys/system_properties.h> #include <stdlib.h> #include <unistd.h> #include <sys/un.h> #include <errno.h> #else #include <resolv.h> #endif #include <stddef.h> #include <string.h> static const struct afd { int a_af; socklen_t a_addrlen; socklen_t a_socklen; int a_off; } afdl [] = { #ifdef INET6 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), offsetof(struct sockaddr_in6, sin6_addr)}, #endif {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), offsetof(struct sockaddr_in, sin_addr)}, {0, 0, 0, 0}, }; struct sockinet { u_char si_len; u_char si_family; u_short si_port; }; static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *, socklen_t, char *, socklen_t, int)); #ifdef INET6 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *, socklen_t, int)); static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t, int)); #endif static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *, socklen_t, char *, socklen_t, int)); static int hexname __P((const u_int8_t *, size_t, char *, socklen_t)); // This should be synchronized to ResponseCode.h static const int DnsProxyQueryResult = 222; /* * Top-level getnameinfo() code. Look at the address family, and pick an * appropriate function to call. */ int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags) { switch (sa->sa_family) { case AF_INET: case AF_INET6: return getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags); #if 0 case AF_LINK: return getnameinfo_link(sa, salen, host, hostlen, serv, servlen, flags); #endif default: return EAI_FAMILY; } } #ifdef ANDROID_CHANGES /* On success length of the host name is returned. A return * value of 0 means there's no host name associated with * the address. On failure -1 is returned in which case * normal execution flow shall continue. */ static int android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr, socklen_t addrLen, int addrFamily) { int sock; const int one = 1; struct sockaddr_un proxy_addr; const char* cache_mode = getenv("ANDROID_DNS_MODE"); FILE* proxy = NULL; int result = -1; if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) { // Don't use the proxy in local mode. This is used by the // proxy itself. return -1; } // Temporary cautious hack to disable the DNS proxy for processes // requesting special treatment. Ideally the DNS proxy should // accomodate these apps, though. char propname[PROP_NAME_MAX]; char propvalue[PROP_VALUE_MAX]; snprintf(propname, sizeof(propname), "net.dns1.%d", getpid()); if (__system_property_get(propname, propvalue) > 0) { return -1; } // create socket sock = socket(AF_UNIX, SOCK_STREAM, 0); if (sock < 0) { return -1; } setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); memset(&proxy_addr, 0, sizeof(proxy_addr)); proxy_addr.sun_family = AF_UNIX; strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", sizeof(proxy_addr.sun_path)); if (TEMP_FAILURE_RETRY(connect(sock, (const struct sockaddr*) (void*) &proxy_addr, sizeof(proxy_addr))) != 0) { close(sock); return -1; } // send request to DnsProxyListener proxy = fdopen(sock,"r+"); if (proxy == NULL) { goto exit; } char buf[INET6_ADDRSTRLEN]; // big enough for IPv4 and IPv6 const char* addrStr = inet_ntop(addrFamily, addr, buf, sizeof(buf)); if (addrStr == NULL) { goto exit; } if (fprintf(proxy, "gethostbyaddr %s %d %d", addrStr, addrLen, addrFamily) < 0) { goto exit; } // literal NULL byte at end, required by FrameworkListener if (fputc(0, proxy) == EOF || fflush(proxy) != 0) { goto exit; } result = 0; char msg_buf[4]; // read result code for gethostbyaddr if (fread(msg_buf, 1, sizeof(msg_buf), proxy) != sizeof(msg_buf)) { goto exit; } int result_code = (int)strtol(msg_buf, NULL, 10); // verify the code itself if (result_code != DnsProxyQueryResult) { goto exit; } uint32_t name_len; if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) { goto exit; } name_len = ntohl(name_len); if (name_len <= 0 || name_len >= nameBufLen) { goto exit; } if (fread(nameBuf, name_len, 1, proxy) != 1) { goto exit; } result = name_len; exit: if (proxy != NULL) { fclose(proxy); } return result; } #endif /* * getnameinfo_inet(): * Format an IPv4 or IPv6 sockaddr into a printable string. */ static int getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags) const struct sockaddr *sa; socklen_t salen; char *host; socklen_t hostlen; char *serv; socklen_t servlen; int flags; { const struct afd *afd; struct servent *sp; struct hostent *hp; u_short port; int family, i; const char *addr; u_int32_t v4a; char numserv[512]; char numaddr[512]; /* sa is checked below */ /* host may be NULL */ /* serv may be NULL */ if (sa == NULL) return EAI_FAIL; #ifdef BSD4_4 if (sa->sa_len != salen) return EAI_FAIL; #endif family = sa->sa_family; for (i = 0; afdl[i].a_af; i++) if (afdl[i].a_af == family) { afd = &afdl[i]; goto found; } return EAI_FAMILY; found: if (salen != afd->a_socklen) return EAI_FAIL; /* network byte order */ port = ((const struct sockinet *)(const void *)sa)->si_port; addr = (const char *)(const void *)sa + afd->a_off; if (serv == NULL || servlen == 0) { /* * do nothing in this case. * in case you are wondering if "&&" is more correct than * "||" here: rfc2553bis-03 says that serv == NULL OR * servlen == 0 means that the caller does not want the result. */ } else { if (flags & NI_NUMERICSERV) sp = NULL; else { sp = getservbyport(port, (flags & NI_DGRAM) ? "udp" : "tcp"); } if (sp) { if (strlen(sp->s_name) + 1 > (size_t)servlen) return EAI_MEMORY; strlcpy(serv, sp->s_name, servlen); } else { snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); if (strlen(numserv) + 1 > (size_t)servlen) return EAI_MEMORY; strlcpy(serv, numserv, servlen); } } switch (sa->sa_family) { case AF_INET: v4a = (u_int32_t) ntohl(((const struct sockaddr_in *) (const void *)sa)->sin_addr.s_addr); if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) flags |= NI_NUMERICHOST; v4a >>= IN_CLASSA_NSHIFT; if (v4a == 0) flags |= NI_NUMERICHOST; break; #ifdef INET6 case AF_INET6: { const struct sockaddr_in6 *sin6; sin6 = (const struct sockaddr_in6 *)(const void *)sa; switch (sin6->sin6_addr.s6_addr[0]) { case 0x00: if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) ; else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) ; else flags |= NI_NUMERICHOST; break; default: if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { flags |= NI_NUMERICHOST; } else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) flags |= NI_NUMERICHOST; break; } } break; #endif } if (host == NULL || hostlen == 0) { /* * do nothing in this case. * in case you are wondering if "&&" is more correct than * "||" here: rfc2553bis-03 says that host == NULL or * hostlen == 0 means that the caller does not want the result. */ } else if (flags & NI_NUMERICHOST) { size_t numaddrlen; /* NUMERICHOST and NAMEREQD conflicts with each other */ if (flags & NI_NAMEREQD) return EAI_NONAME; switch(afd->a_af) { #ifdef INET6 case AF_INET6: { int error; if ((error = ip6_parsenumeric(sa, addr, host, hostlen, flags)) != 0) return(error); break; } #endif default: if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) == NULL) return EAI_SYSTEM; numaddrlen = strlen(numaddr); if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ return EAI_MEMORY; strlcpy(host, numaddr, hostlen); break; } } else { #ifdef ANDROID_CHANGES struct hostent android_proxy_hostent; char android_proxy_buf[MAXDNAME]; int hostnamelen = android_gethostbyaddr_proxy(android_proxy_buf, MAXDNAME, addr, afd->a_addrlen, afd->a_af); if (hostnamelen > 0) { hp = &android_proxy_hostent; hp->h_name = android_proxy_buf; } else if (!hostnamelen) { hp = NULL; } else { hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af); } #else hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af); #endif if (hp) { #if 0 /* * commented out, since "for local host" is not * implemented here - see RFC2553 p30 */ if (flags & NI_NOFQDN) { char *p; p = strchr(hp->h_name, '.'); if (p) *p = '\0'; } #endif if (strlen(hp->h_name) + 1 > (size_t)hostlen) { return EAI_MEMORY; } strlcpy(host, hp->h_name, hostlen); } else { if (flags & NI_NAMEREQD) return EAI_NONAME; switch(afd->a_af) { #ifdef INET6 case AF_INET6: { int error; if ((error = ip6_parsenumeric(sa, addr, host, hostlen, flags)) != 0) return(error); break; } #endif default: if (inet_ntop(afd->a_af, addr, host, hostlen) == NULL) return EAI_SYSTEM; break; } } } return(0); } #ifdef INET6 static int ip6_parsenumeric(sa, addr, host, hostlen, flags) const struct sockaddr *sa; const char *addr; char *host; socklen_t hostlen; int flags; { size_t numaddrlen; char numaddr[512]; assert(sa != NULL); assert(addr != NULL); assert(host != NULL); if (hostlen < 0) return EAI_OVERFLOW; if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) return EAI_SYSTEM; numaddrlen = strlen(numaddr); if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ return EAI_OVERFLOW; strlcpy(host, numaddr, hostlen); if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) { char zonebuf[MAXHOSTNAMELEN]; int zonelen; zonelen = ip6_sa2str( (const struct sockaddr_in6 *)(const void *)sa, zonebuf, sizeof(zonebuf), flags); if (zonelen < 0) return EAI_OVERFLOW; if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen) return EAI_OVERFLOW; /* construct <numeric-addr><delim><zoneid> */ memcpy(host + numaddrlen + 1, zonebuf, (size_t)zonelen); host[numaddrlen] = SCOPE_DELIMITER; host[numaddrlen + 1 + zonelen] = '\0'; } return 0; } /* ARGSUSED */ static int ip6_sa2str(sa6, buf, bufsiz, flags) const struct sockaddr_in6 *sa6; char *buf; size_t bufsiz; int flags; { unsigned int ifindex; const struct in6_addr *a6; int n; assert(sa6 != NULL); assert(buf != NULL); ifindex = (unsigned int)sa6->sin6_scope_id; a6 = &sa6->sin6_addr; #ifdef NI_NUMERICSCOPE if ((flags & NI_NUMERICSCOPE) != 0) { n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); if (n < 0 || n >= bufsiz) return -1; else return n; } #endif /* if_indextoname() does not take buffer size. not a good api... */ if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) && bufsiz >= IF_NAMESIZE) { char *p = if_indextoname(ifindex, buf); if (p) { return(strlen(p)); } } /* last resort */ n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); if (n < 0 || (size_t) n >= bufsiz) return -1; else return n; } #endif /* INET6 */ /* * getnameinfo_link(): * Format a link-layer address into a printable format, paying attention to * the interface type. */ /* ARGSUSED */ static int getnameinfo_link(const struct sockaddr *sa, socklen_t salen, char *host, socklen_t hostlen, char *serv, socklen_t servlen, int flags) { const struct sockaddr_dl *sdl = (const struct sockaddr_dl *)(const void *)sa; const struct ieee1394_hwaddr *iha; int n; if (serv != NULL && servlen > 0) *serv = '\0'; if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { n = snprintf(host, hostlen, "link#%u", sdl->sdl_index); if (n < 0 || (socklen_t) n > hostlen) { *host = '\0'; return EAI_MEMORY; } return 0; } switch (sdl->sdl_type) { #ifdef IFT_ECONET case IFT_ECONET: if (sdl->sdl_alen < 2) return EAI_FAMILY; if (CLLADDR(sdl)[1] == 0) n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]); else n = snprintf(host, hostlen, "%u.%u", CLLADDR(sdl)[1], CLLADDR(sdl)[0]); if (n < 0 || (socklen_t) n >= hostlen) { *host = '\0'; return EAI_MEMORY; } else return 0; #endif case IFT_IEEE1394: if (sdl->sdl_alen < sizeof(iha->iha_uid)) return EAI_FAMILY; iha = (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl); return hexname(iha->iha_uid, sizeof(iha->iha_uid), host, hostlen); /* * The following have zero-length addresses. * IFT_ATM (net/if_atmsubr.c) * IFT_FAITH (net/if_faith.c) * IFT_GIF (net/if_gif.c) * IFT_LOOP (net/if_loop.c) * IFT_PPP (net/if_ppp.c, net/if_spppsubr.c) * IFT_SLIP (net/if_sl.c, net/if_strip.c) * IFT_STF (net/if_stf.c) * IFT_L2VLAN (net/if_vlan.c) * IFT_PROPVIRTUAL (net/if_bridge.h> */ /* * The following use IPv4 addresses as link-layer addresses: * IFT_OTHER (net/if_gre.c) */ case IFT_ARCNET: /* default below is believed correct for all these. */ case IFT_ETHER: case IFT_FDDI: case IFT_HIPPI: case IFT_ISO88025: default: return hexname((const u_int8_t *)CLLADDR(sdl), (size_t)sdl->sdl_alen, host, hostlen); } } static int hexname(cp, len, host, hostlen) const u_int8_t *cp; char *host; size_t len; socklen_t hostlen; { int n; size_t i; char *outp = host; *outp = '\0'; for (i = 0; i < len; i++) { n = snprintf(outp, hostlen, "%s%02x", i ? ":" : "", cp[i]); if (n < 0 || (socklen_t) n >= hostlen) { *host = '\0'; return EAI_MEMORY; } outp += n; hostlen -= n; } return 0; }