mDNSBSD.c revision 1.1.16.1
1 /* -*- Mode: C; tab-width: 4 -*- 2 * 3 * Copyright (c) 2002-2004 Apple Computer, Inc. All rights reserved. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 #include "mDNSUNP.h" 19 #include <ifaddrs.h> 20 21 #include <assert.h> 22 #include <err.h> 23 #include <errno.h> 24 #include <string.h> 25 #include <stdlib.h> 26 #include <unistd.h> 27 #include <netinet/in.h> 28 #include <netinet/in_var.h> 29 #include <net/if_dl.h> 30 31 32 ssize_t 33 recvfrom_flags(int fd, void *ptr, size_t nbytes, int *flagsp, 34 struct sockaddr *sa, socklen_t *salenptr, struct my_in_pktinfo *pktp, 35 u_char *ttl) 36 { 37 struct msghdr msg; 38 struct iovec iov[1]; 39 ssize_t n; 40 41 #ifdef CMSG_FIRSTHDR 42 struct cmsghdr *cmptr; 43 union { 44 struct cmsghdr cm; 45 char control[1024]; 46 } control_un; 47 48 *ttl = 255; // If kernel fails to provide TTL data then assume the TTL was 255 as it should be 49 50 msg.msg_control = control_un.control; 51 msg.msg_controllen = sizeof(control_un.control); 52 msg.msg_flags = 0; 53 #else 54 memset(&msg, 0, sizeof(msg)); /* make certain msg_accrightslen = 0 */ 55 #endif /* CMSG_FIRSTHDR */ 56 57 msg.msg_name = (char *) sa; 58 msg.msg_namelen = *salenptr; 59 iov[0].iov_base = (char *)ptr; 60 iov[0].iov_len = nbytes; 61 msg.msg_iov = iov; 62 msg.msg_iovlen = 1; 63 64 if ( (n = recvmsg(fd, &msg, *flagsp)) < 0) 65 return(n); 66 67 *salenptr = msg.msg_namelen; /* pass back results */ 68 if (pktp) { 69 /* 0.0.0.0, i/f = -1 */ 70 /* We set the interface to -1 so that the caller can 71 tell whether we returned a meaningful value or 72 just some default. Previously this code just 73 set the value to 0, but I'm concerned that 0 74 might be a valid interface value. 75 */ 76 memset(pktp, 0, sizeof(struct my_in_pktinfo)); 77 pktp->ipi_ifindex = -1; 78 } 79 /* end recvfrom_flags1 */ 80 81 /* include recvfrom_flags2 */ 82 #ifndef CMSG_FIRSTHDR 83 #warning CMSG_FIRSTHDR not defined. Will not be able to determine destination address, received interface, etc. 84 *flagsp = 0; /* pass back results */ 85 return(n); 86 #else 87 88 *flagsp = msg.msg_flags; /* pass back results */ 89 if (msg.msg_controllen < (socklen_t)sizeof(struct cmsghdr) || 90 (msg.msg_flags & MSG_CTRUNC) || pktp == NULL) 91 return(n); 92 93 for (cmptr = CMSG_FIRSTHDR(&msg); cmptr != NULL; 94 cmptr = CMSG_NXTHDR(&msg, cmptr)) { 95 96 #ifdef IP_PKTINFO 97 #if in_pktinfo_definition_is_missing 98 struct in_pktinfo 99 { 100 int ipi_ifindex; 101 struct in_addr ipi_spec_dst; 102 struct in_addr ipi_addr; 103 }; 104 #endif 105 if (cmptr->cmsg_level == IPPROTO_IP && 106 cmptr->cmsg_type == IP_PKTINFO) { 107 struct in_pktinfo *tmp; 108 struct sockaddr_in *sin = (struct sockaddr_in*)&pktp->ipi_addr; 109 110 tmp = (struct in_pktinfo *) CMSG_DATA(cmptr); 111 sin->sin_family = AF_INET; 112 sin->sin_addr = tmp->ipi_addr; 113 sin->sin_port = 0; 114 pktp->ipi_ifindex = tmp->ipi_ifindex; 115 continue; 116 } 117 #endif 118 119 #ifdef IP_RECVDSTADDR 120 if (cmptr->cmsg_level == IPPROTO_IP && 121 cmptr->cmsg_type == IP_RECVDSTADDR) { 122 struct sockaddr_in *sin = (struct sockaddr_in*)&pktp->ipi_addr; 123 124 sin->sin_family = AF_INET; 125 sin->sin_addr = *(struct in_addr*)CMSG_DATA(cmptr); 126 sin->sin_port = 0; 127 continue; 128 } 129 #endif 130 131 #ifdef IP_RECVIF 132 if (cmptr->cmsg_level == IPPROTO_IP && 133 cmptr->cmsg_type == IP_RECVIF) { 134 struct sockaddr_dl *sdl = (struct sockaddr_dl *) CMSG_DATA(cmptr); 135 #ifndef HAVE_BROKEN_RECVIF_NAME 136 int nameLen = (sdl->sdl_nlen < IFI_NAME - 1) ? sdl->sdl_nlen : (IFI_NAME - 1); 137 strncpy(pktp->ipi_ifname, sdl->sdl_data, nameLen); 138 #endif 139 pktp->ipi_ifindex = sdl->sdl_index; 140 #ifdef HAVE_BROKEN_RECVIF_NAME 141 if (sdl->sdl_index == 0) { 142 pktp->ipi_ifindex = *(uint_t*)sdl; 143 } 144 #endif 145 assert(pktp->ipi_ifname[IFI_NAME - 1] == 0); 146 // null terminated because of memset above 147 continue; 148 } 149 #endif 150 151 #ifdef IP_RECVTTL 152 if (cmptr->cmsg_level == IPPROTO_IP && 153 cmptr->cmsg_type == IP_RECVTTL) { 154 *ttl = *(u_char*)CMSG_DATA(cmptr); 155 continue; 156 } 157 else if (cmptr->cmsg_level == IPPROTO_IP && 158 cmptr->cmsg_type == IP_TTL) { // some implementations seem to send IP_TTL instead of IP_RECVTTL 159 *ttl = *(int*)CMSG_DATA(cmptr); 160 continue; 161 } 162 #endif 163 164 #if defined(IPV6_PKTINFO) && HAVE_IPV6 165 if (cmptr->cmsg_level == IPPROTO_IPV6 && 166 cmptr->cmsg_type == IPV6_2292_PKTINFO) { 167 struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&pktp->ipi_addr; 168 struct in6_pktinfo *ip6_info = (struct in6_pktinfo*)CMSG_DATA(cmptr); 169 170 sin6->sin6_family = AF_INET6; 171 #ifndef NOT_HAVE_SA_LEN 172 sin6->sin6_len = sizeof(*sin6); 173 #endif 174 sin6->sin6_addr = ip6_info->ipi6_addr; 175 sin6->sin6_flowinfo = 0; 176 sin6->sin6_scope_id = 0; 177 sin6->sin6_port = 0; 178 pktp->ipi_ifindex = ip6_info->ipi6_ifindex; 179 continue; 180 } 181 #endif 182 183 #if defined(IPV6_HOPLIMIT) && HAVE_IPV6 184 if (cmptr->cmsg_level == IPPROTO_IPV6 && 185 cmptr->cmsg_type == IPV6_2292_HOPLIMIT) { 186 *ttl = *(int*)CMSG_DATA(cmptr); 187 continue; 188 } 189 #endif 190 assert(0); // unknown ancillary data 191 } 192 return(n); 193 #endif /* CMSG_FIRSTHDR */ 194 } 195
Indexes created Thu Jul 30 00:24:59 UTC 2026