1 /* $OpenBSD: getnameinfo.c,v 1.10 2020/12/21 09:40:35 eric Exp $ */ 2 /* 3 * Copyright (c) 2012 Eric Faurot <eric@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <sys/types.h> 19 #include <sys/socket.h> 20 #include <net/if.h> 21 #include <arpa/inet.h> 22 #include <netinet/in.h> 23 #include <netdb.h> 24 25 #include <asr.h> 26 #include <errno.h> 27 #include <resolv.h> 28 #include <string.h> 29 30 static size_t asr_print_addr(const struct sockaddr *, char *, size_t); 31 static size_t asr_print_port(const struct sockaddr *, const char *, char *, size_t); 32 33 #define SA_IN(sa) ((struct sockaddr_in*)(sa)) 34 #define SA_IN6(sa) ((struct sockaddr_in6*)(sa)) 35 36 /* 37 * Print the textual representation (as given by inet_ntop(3)) of the address 38 * set in "sa". 39 * 40 * Return the total length of the string it tried to create or 0 if an error 41 * occured, in which case errno is set. On success, the constructed string 42 * is guaranteed to be NUL-terminated. Overflow must be detected by checking 43 * the returned size against buflen. 44 * 45 */ 46 static size_t 47 asr_print_addr(const struct sockaddr *sa, char *buf, size_t buflen) 48 { 49 unsigned int ifidx; 50 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")]; 51 char scope[IF_NAMESIZE + 1], *ifname; 52 const void *addr; 53 size_t s; 54 55 switch(sa->sa_family) { 56 case AF_INET: 57 addr = &SA_IN(sa)->sin_addr; 58 break; 59 case AF_INET6: 60 addr = &SA_IN6(sa)->sin6_addr; 61 break; 62 default: 63 errno = EINVAL; 64 return (0); 65 } 66 67 if (inet_ntop(sa->sa_family, addr, tmp, sizeof(tmp)) == NULL) 68 return (0); /* errno set */ 69 70 s = strlcpy(buf, tmp, buflen); 71 72 if (sa->sa_family == AF_INET6 && SA_IN6(sa)->sin6_scope_id) { 73 74 scope[0] = SCOPE_DELIMITER; 75 scope[1] = '\0'; 76 77 ifidx = SA_IN6(sa)->sin6_scope_id; 78 ifname = NULL; 79 80 if (IN6_IS_ADDR_LINKLOCAL(&(SA_IN6(sa)->sin6_addr)) || 81 IN6_IS_ADDR_MC_LINKLOCAL(&(SA_IN6(sa)->sin6_addr)) || 82 IN6_IS_ADDR_MC_INTFACELOCAL(&(SA_IN6(sa)->sin6_addr))) 83 ifname = if_indextoname(ifidx, scope + 1); 84 85 if (ifname == NULL) 86 (void)snprintf(scope + 1, sizeof(scope) - 1, "%u", ifidx); 87 88 if (s < buflen) 89 (void)strlcat(buf, scope, buflen); 90 91 s += strlen(scope); 92 } 93 94 return (s); 95 } 96 97 /* 98 * Print the textual representation of the port set on "sa". 99 * 100 * If proto is not NULL, it is used as parameter to "getservbyport_r(3)" to 101 * return a service name. If it's not set, or if no matching service is found, 102 * it prints the portno. 103 * 104 * Return the total length of the string it tried to create or 0 if an error 105 * occured, in which case errno is set. On success, the constructed string 106 * is guaranteed to be NUL-terminated. Overflow must be detected by checking 107 * the returned size against buflen. 108 */ 109 static size_t 110 asr_print_port(const struct sockaddr *sa, const char *proto, char *buf, size_t buflen) 111 { 112 struct servent s; 113 struct servent_data sd; 114 int port, r, saved_errno; 115 size_t n; 116 117 switch(sa->sa_family) { 118 case AF_INET: 119 port = SA_IN(sa)->sin_port; 120 break; 121 case AF_INET6: 122 port = SA_IN6(sa)->sin6_port; 123 break; 124 default: 125 errno = EINVAL; 126 return (0); 127 } 128 129 if (proto) { 130 memset(&sd, 0, sizeof (sd)); 131 saved_errno = errno; 132 r = getservbyport_r(port, proto, &s, &sd); 133 if (r == 0) 134 n = strlcpy(buf, s.s_name, buflen); 135 endservent_r(&sd); 136 errno = saved_errno; 137 if (r == 0) 138 return (n); 139 } 140 141 r = snprintf(buf, buflen, "%u", ntohs(port)); 142 if (r < 0 || r >= buflen) /* Actually, this can not happen */ 143 return (0); 144 145 return (r); 146 } 147 148 int 149 getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, 150 size_t hostlen, char *serv, size_t servlen, int flags) 151 { 152 struct asr_query *as; 153 struct asr_result ar; 154 int saved_errno = errno; 155 const char *proto; 156 size_t r; 157 158 /* 159 * Take a shortcut if we don't care about hostname, 160 * or if NI_NUMERICHOST is set. 161 */ 162 if (host == NULL || hostlen == 0 || 163 (host && hostlen && (flags & NI_NUMERICHOST))) { 164 if (host) { 165 r = asr_print_addr(sa, host, hostlen); 166 if (r == 0) 167 return (EAI_SYSTEM); /* errno set */ 168 if (r >= hostlen) 169 return (EAI_OVERFLOW); 170 } 171 172 if (serv && servlen) { 173 if (flags & NI_NUMERICSERV) 174 proto = NULL; 175 else 176 proto = (flags & NI_DGRAM) ? "udp" : "tcp"; 177 r = asr_print_port(sa, proto, serv, servlen); 178 if (r == 0) 179 return (EAI_SYSTEM); /* errno set */ 180 if (r >= servlen) 181 return (EAI_OVERFLOW); 182 } 183 184 errno = saved_errno; 185 return (0); 186 } 187 188 res_init(); 189 190 as = getnameinfo_async(sa, salen, host, hostlen, serv, servlen, flags, 191 NULL); 192 if (as == NULL) { 193 if (errno == ENOMEM) { 194 errno = saved_errno; 195 return (EAI_MEMORY); 196 } 197 return (EAI_SYSTEM); 198 } 199 200 asr_run_sync(as, &ar); 201 if (ar.ar_gai_errno == EAI_SYSTEM) 202 errno = ar.ar_errno; 203 204 return (ar.ar_gai_errno); 205 } 206 DEF_WEAK(getnameinfo); 207