int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr, int addrlen, int family, struct hostent **host) { unsigned int qdcount, ancount; int status, i, rr_type, rr_class, rr_len; long len; const unsigned char *aptr; char *ptrname, *hostname, *rr_name, *rr_data; struct hostent *hostent; int aliascnt = 0; int alias_alloc = 8; char ** aliases; /* Set *host to NULL for all failure cases. */ *host = NULL; /* Give up if abuf doesn't have room for a header. */ if (alen < HFIXEDSZ) return ARES_EBADRESP; /* Fetch the question and answer count from the header. */ qdcount = DNS_HEADER_QDCOUNT(abuf); ancount = DNS_HEADER_ANCOUNT(abuf); if (qdcount != 1) return ARES_EBADRESP; /* Expand the name from the question, and skip past the question. */ aptr = abuf + HFIXEDSZ; status = ares__expand_name_for_response(aptr, abuf, alen, &ptrname, &len); if (status != ARES_SUCCESS) return status; if (aptr + len + QFIXEDSZ > abuf + alen) { free(ptrname); return ARES_EBADRESP; } aptr += len + QFIXEDSZ; /* Examine each answer resource record (RR) in turn. */ hostname = NULL; aliases = malloc(alias_alloc * sizeof(char *)); if (!aliases) { free(ptrname); return ARES_ENOMEM; } for (i = 0; i < (int)ancount; i++) { /* Decode the RR up to the data field. */ status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len); if (status != ARES_SUCCESS) break; aptr += len; if (aptr + RRFIXEDSZ > abuf + alen) { free(rr_name); status = ARES_EBADRESP; break; } rr_type = DNS_RR_TYPE(aptr); rr_class = DNS_RR_CLASS(aptr); rr_len = DNS_RR_LEN(aptr); aptr += RRFIXEDSZ; if (rr_class == C_IN && rr_type == T_PTR && strcasecmp(rr_name, ptrname) == 0) { /* Decode the RR data and set hostname to it. */ status = ares__expand_name_for_response(aptr, abuf, alen, &rr_data, &len); if (status != ARES_SUCCESS) { free(rr_name); break; } if (hostname) free(hostname); hostname = rr_data; aliases[aliascnt] = malloc((strlen(rr_data)+1) * sizeof(char)); if (!aliases[aliascnt]) { free(rr_name); status = ARES_ENOMEM; break; } strncpy(aliases[aliascnt], rr_data, strlen(rr_data)+1); aliascnt++; if (aliascnt >= alias_alloc) { char **ptr; alias_alloc *= 2; ptr = realloc(aliases, alias_alloc * sizeof(char *)); if(!ptr) { free(rr_name); status = ARES_ENOMEM; break; } aliases = ptr; } } if (rr_class == C_IN && rr_type == T_CNAME) { /* Decode the RR data and replace ptrname with it. */ status = ares__expand_name_for_response(aptr, abuf, alen, &rr_data, &len); if (status != ARES_SUCCESS) { free(rr_name); break; } free(ptrname); ptrname = rr_data; } free(rr_name); aptr += rr_len; if (aptr > abuf + alen) { status = ARES_EBADRESP; break; } } if (status == ARES_SUCCESS && !hostname) status = ARES_ENODATA; if (status == ARES_SUCCESS) { /* We got our answer. Allocate memory to build the host entry. */ hostent = malloc(sizeof(struct hostent)); if (hostent) { hostent->h_addr_list = malloc(2 * sizeof(char *)); if (hostent->h_addr_list) { hostent->h_addr_list[0] = malloc(addrlen); if (hostent->h_addr_list[0]) { hostent->h_aliases = malloc((aliascnt+1) * sizeof (char *)); if (hostent->h_aliases) { /* Fill in the hostent and return successfully. */ hostent->h_name = hostname; for (i=0 ; i<aliascnt ; i++) hostent->h_aliases[i] = aliases[i]; hostent->h_aliases[aliascnt] = NULL; hostent->h_addrtype = aresx_sitoss(family); hostent->h_length = aresx_sitoss(addrlen); memcpy(hostent->h_addr_list[0], addr, addrlen); hostent->h_addr_list[1] = NULL; *host = hostent; free(aliases); free(ptrname); return ARES_SUCCESS; } free(hostent->h_addr_list[0]); } free(hostent->h_addr_list); } free(hostent); } status = ARES_ENOMEM; } for (i=0 ; i<aliascnt ; i++) if (aliases[i]) free(aliases[i]); free(aliases); if (hostname) free(hostname); free(ptrname); return status; }
/* If the name looks like an IP address, fake up a host entry, end the * query immediately, and return true. Otherwise return false. */ static int fake_hostent(const char *name, int family, ares_host_callback callback, void *arg) { struct hostent hostent; char *aliases[1] = { NULL }; char *addrs[2]; int result = 0; struct in_addr in; struct ares_in6_addr in6; if (family == AF_INET || family == AF_INET6) { /* It only looks like an IP address if it's all numbers and dots. */ int numdots = 0, valid = 1; const char *p; for (p = name; *p; p++) { if (!ISDIGIT(*p) && *p != '.') { valid = 0; break; } else if (*p == '.') { numdots++; } } /* if we don't have 3 dots, it is illegal * (although inet_addr doesn't think so). */ if (numdots != 3 || !valid) result = 0; else result = ((in.s_addr = inet_addr(name)) == INADDR_NONE ? 0 : 1); if (result) family = AF_INET; } if (family == AF_INET6) result = (ares_inet_pton(AF_INET6, name, &in6) < 1 ? 0 : 1); if (!result) return 0; if (family == AF_INET) { hostent.h_length = (int)sizeof(struct in_addr); addrs[0] = (char *)∈ } else if (family == AF_INET6) { hostent.h_length = (int)sizeof(struct ares_in6_addr); addrs[0] = (char *)&in6; } /* Duplicate the name, to avoid a constness violation. */ hostent.h_name = ares_strdup(name); if (!hostent.h_name) { callback(arg, ARES_ENOMEM, 0, NULL); return 1; } /* Fill in the rest of the host structure and terminate the query. */ addrs[1] = NULL; hostent.h_aliases = aliases; hostent.h_addrtype = aresx_sitoss(family); hostent.h_addr_list = addrs; callback(arg, ARES_SUCCESS, 0, &hostent); ares_free((char *)(hostent.h_name)); return 1; }
int ares__get_hostent(FILE *fp, int family, struct hostent **host) { char *line = NULL, *p, *q, **alias; char *txtaddr, *txthost, *txtalias; int status; size_t addrlen, linesize, naliases; struct ares_addr addr; struct hostent *hostent = NULL; *host = NULL; /* Assume failure */ /* Validate family */ switch (family) { case AF_INET: case AF_INET6: case AF_UNSPEC: break; default: return ARES_EBADFAMILY; } while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS) { /* Trim line comment. */ p = line; while (*p && (*p != '#')) p++; *p = '\0'; /* Trim trailing whitespace. */ q = p - 1; while ((q >= line) && ISSPACE(*q)) q--; *++q = '\0'; /* Skip leading whitespace. */ p = line; while (*p && ISSPACE(*p)) p++; if (!*p) /* Ignore line if empty. */ continue; /* Pointer to start of IPv4 or IPv6 address part. */ txtaddr = p; /* Advance past address part. */ while (*p && !ISSPACE(*p)) p++; if (!*p) /* Ignore line if reached end of line. */ continue; /* Null terminate address part. */ *p = '\0'; /* Advance to host name */ p++; while (*p && ISSPACE(*p)) p++; if (!*p) /* Ignore line if reached end of line. */ continue; /* LCOV_EXCL_LINE: trailing whitespace already stripped */ /* Pointer to start of host name. */ txthost = p; /* Advance past host name. */ while (*p && !ISSPACE(*p)) p++; /* Pointer to start of first alias. */ txtalias = NULL; if (*p) { q = p + 1; while (*q && ISSPACE(*q)) q++; if (*q) txtalias = q; } /* Null terminate host name. */ *p = '\0'; /* find out number of aliases. */ naliases = 0; if (txtalias) { p = txtalias; while (*p) { while (*p && !ISSPACE(*p)) p++; while (*p && ISSPACE(*p)) p++; naliases++; } } /* Convert address string to network address for the requested family. */ addrlen = 0; addr.family = AF_UNSPEC; addr.addrV4.s_addr = INADDR_NONE; if ((family == AF_INET) || (family == AF_UNSPEC)) { addr.addrV4.s_addr = inet_addr(txtaddr); if (addr.addrV4.s_addr != INADDR_NONE) { /* Actual network address family and length. */ addr.family = AF_INET; addrlen = sizeof(addr.addrV4); } } if ((family == AF_INET6) || ((family == AF_UNSPEC) && (!addrlen))) { if (ares_inet_pton(AF_INET6, txtaddr, &addr.addrV6) > 0) { /* Actual network address family and length. */ addr.family = AF_INET6; addrlen = sizeof(addr.addrV6); } } if (!addrlen) /* Ignore line if invalid address string for the requested family. */ continue; /* ** Actual address family possible values are AF_INET and AF_INET6 only. */ /* Allocate memory for the hostent structure. */ hostent = ares_malloc(sizeof(struct hostent)); if (!hostent) break; /* Initialize fields for out of memory condition. */ hostent->h_aliases = NULL; hostent->h_addr_list = NULL; /* Copy official host name. */ hostent->h_name = ares_strdup(txthost); if (!hostent->h_name) break; /* Copy network address. */ hostent->h_addr_list = ares_malloc(2 * sizeof(char *)); if (!hostent->h_addr_list) break; hostent->h_addr_list[1] = NULL; hostent->h_addr_list[0] = ares_malloc(addrlen); if (!hostent->h_addr_list[0]) break; if (addr.family == AF_INET) memcpy(hostent->h_addr_list[0], &addr.addrV4, sizeof(addr.addrV4)); else memcpy(hostent->h_addr_list[0], &addr.addrV6, sizeof(addr.addrV6)); /* Copy aliases. */ hostent->h_aliases = ares_malloc((naliases + 1) * sizeof(char *)); if (!hostent->h_aliases) break; alias = hostent->h_aliases; while (naliases) *(alias + naliases--) = NULL; *alias = NULL; while (txtalias) { p = txtalias; while (*p && !ISSPACE(*p)) p++; q = p; while (*q && ISSPACE(*q)) q++; *p = '\0'; if ((*alias = ares_strdup(txtalias)) == NULL) break; alias++; txtalias = *q ? q : NULL; } if (txtalias) /* Alias memory allocation failure. */ break; /* Copy actual network address family and length. */ hostent->h_addrtype = aresx_sitoss(addr.family); hostent->h_length = aresx_uztoss(addrlen); /* Free line buffer. */ ares_free(line); /* Return hostent successfully */ *host = hostent; return ARES_SUCCESS; } /* If allocated, free line buffer. */ if (line) ares_free(line); if (status == ARES_SUCCESS) { /* Memory allocation failure; clean up. */ if (hostent) { if (hostent->h_name) ares_free((char *) hostent->h_name); if (hostent->h_aliases) { for (alias = hostent->h_aliases; *alias; alias++) ares_free(*alias); ares_free(hostent->h_aliases); } if (hostent->h_addr_list) { if (hostent->h_addr_list[0]) ares_free(hostent->h_addr_list[0]); ares_free(hostent->h_addr_list); } ares_free(hostent); } return ARES_ENOMEM; } return status; }