1/* 2 * libipq.c 3 * 4 * IPQ userspace library. 5 * 6 * Please note that this library is still developmental, and there may 7 * be some API changes. 8 * 9 * Author: James Morris <jmorris@intercode.com.au> 10 * 11 * 07-11-2001 Modified by Fernando Anton to add support for IPv6. 12 * 13 * Copyright (c) 2000-2001 Netfilter Core Team 14 * 15 * This program is free software; you can redistribute it and/or modify 16 * it under the terms of the GNU General Public License as published by 17 * the Free Software Foundation; either version 2 of the License, or 18 * (at your option) any later version. 19 * 20 * This program is distributed in the hope that it will be useful, 21 * but WITHOUT ANY WARRANTY; without even the implied warranty of 22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 23 * GNU General Public License for more details. 24 * 25 */ 26 27#include <stdlib.h> 28#include <stdio.h> 29#include <string.h> 30#include <unistd.h> 31#include <sys/time.h> 32#include <sys/types.h> 33 34#include <libipq/libipq.h> 35 36/**************************************************************************** 37 * 38 * Private interface 39 * 40 ****************************************************************************/ 41 42enum { 43 IPQ_ERR_NONE = 0, 44 IPQ_ERR_IMPL, 45 IPQ_ERR_HANDLE, 46 IPQ_ERR_SOCKET, 47 IPQ_ERR_BIND, 48 IPQ_ERR_BUFFER, 49 IPQ_ERR_RECV, 50 IPQ_ERR_NLEOF, 51 IPQ_ERR_ADDRLEN, 52 IPQ_ERR_STRUNC, 53 IPQ_ERR_RTRUNC, 54 IPQ_ERR_NLRECV, 55 IPQ_ERR_SEND, 56 IPQ_ERR_SUPP, 57 IPQ_ERR_RECVBUF, 58 IPQ_ERR_TIMEOUT, 59 IPQ_ERR_PROTOCOL 60}; 61#define IPQ_MAXERR IPQ_ERR_PROTOCOL 62 63struct ipq_errmap_t { 64 int errcode; 65 char *message; 66} ipq_errmap[] = { 67 { IPQ_ERR_NONE, "Unknown error" }, 68 { IPQ_ERR_IMPL, "Implementation error" }, 69 { IPQ_ERR_HANDLE, "Unable to create netlink handle" }, 70 { IPQ_ERR_SOCKET, "Unable to create netlink socket" }, 71 { IPQ_ERR_BIND, "Unable to bind netlink socket" }, 72 { IPQ_ERR_BUFFER, "Unable to allocate buffer" }, 73 { IPQ_ERR_RECV, "Failed to receive netlink message" }, 74 { IPQ_ERR_NLEOF, "Received EOF on netlink socket" }, 75 { IPQ_ERR_ADDRLEN, "Invalid peer address length" }, 76 { IPQ_ERR_STRUNC, "Sent message truncated" }, 77 { IPQ_ERR_RTRUNC, "Received message truncated" }, 78 { IPQ_ERR_NLRECV, "Received error from netlink" }, 79 { IPQ_ERR_SEND, "Failed to send netlink message" }, 80 { IPQ_ERR_SUPP, "Operation not supported" }, 81 { IPQ_ERR_RECVBUF, "Receive buffer size invalid" }, 82 { IPQ_ERR_TIMEOUT, "Timeout"}, 83 { IPQ_ERR_PROTOCOL, "Invalid protocol specified" } 84}; 85 86static int ipq_errno = IPQ_ERR_NONE; 87 88static ssize_t ipq_netlink_sendto(const struct ipq_handle *h, 89 const void *msg, size_t len); 90 91static ssize_t ipq_netlink_recvfrom(const struct ipq_handle *h, 92 unsigned char *buf, size_t len, 93 int timeout); 94 95static ssize_t ipq_netlink_sendmsg(const struct ipq_handle *h, 96 const struct msghdr *msg, 97 unsigned int flags); 98 99static char *ipq_strerror(int errcode); 100 101static ssize_t ipq_netlink_sendto(const struct ipq_handle *h, 102 const void *msg, size_t len) 103{ 104 int status = sendto(h->fd, msg, len, 0, 105 (struct sockaddr *)&h->peer, sizeof(h->peer)); 106 if (status < 0) 107 ipq_errno = IPQ_ERR_SEND; 108 return status; 109} 110 111static ssize_t ipq_netlink_sendmsg(const struct ipq_handle *h, 112 const struct msghdr *msg, 113 unsigned int flags) 114{ 115 int status = sendmsg(h->fd, msg, flags); 116 if (status < 0) 117 ipq_errno = IPQ_ERR_SEND; 118 return status; 119} 120 121static ssize_t ipq_netlink_recvfrom(const struct ipq_handle *h, 122 unsigned char *buf, size_t len, 123 int timeout) 124{ 125 int addrlen, status; 126 struct nlmsghdr *nlh; 127 128 if (len < sizeof(struct nlmsgerr)) { 129 ipq_errno = IPQ_ERR_RECVBUF; 130 return -1; 131 } 132 addrlen = sizeof(h->peer); 133 134 if (timeout != 0) { 135 int ret; 136 struct timeval tv; 137 fd_set read_fds; 138 139 if (timeout < 0) { 140 /* non-block non-timeout */ 141 tv.tv_sec = 0; 142 tv.tv_usec = 0; 143 } else { 144 tv.tv_sec = timeout / 1000000; 145 tv.tv_usec = timeout % 1000000; 146 } 147 148 FD_ZERO(&read_fds); 149 FD_SET(h->fd, &read_fds); 150 ret = select(h->fd+1, &read_fds, NULL, NULL, &tv); 151 if (ret < 0) { 152 if (errno == EINTR) { 153 return 0; 154 } else { 155 ipq_errno = IPQ_ERR_RECV; 156 return -1; 157 } 158 } 159 if (!FD_ISSET(h->fd, &read_fds)) { 160 ipq_errno = IPQ_ERR_TIMEOUT; 161 return 0; 162 } 163 } 164 status = recvfrom(h->fd, buf, len, 0, 165 (struct sockaddr *)&h->peer, &addrlen); 166 if (status < 0) { 167 ipq_errno = IPQ_ERR_RECV; 168 return status; 169 } 170 if (addrlen != sizeof(h->peer)) { 171 ipq_errno = IPQ_ERR_RECV; 172 return -1; 173 } 174 if (status == 0) { 175 ipq_errno = IPQ_ERR_NLEOF; 176 return -1; 177 } 178 nlh = (struct nlmsghdr *)buf; 179 if (nlh->nlmsg_flags & MSG_TRUNC || nlh->nlmsg_len > status) { 180 ipq_errno = IPQ_ERR_RTRUNC; 181 return -1; 182 } 183 return status; 184} 185 186static char *ipq_strerror(int errcode) 187{ 188 if (errcode < 0 || errcode > IPQ_MAXERR) 189 errcode = IPQ_ERR_IMPL; 190 return ipq_errmap[errcode].message; 191} 192 193/**************************************************************************** 194 * 195 * Public interface 196 * 197 ****************************************************************************/ 198 199/* 200 * Create and initialise an ipq handle. 201 */ 202struct ipq_handle *ipq_create_handle(u_int32_t flags, u_int32_t protocol) 203{ 204 int status; 205 struct ipq_handle *h; 206 207 h = (struct ipq_handle *)malloc(sizeof(struct ipq_handle)); 208 if (h == NULL) { 209 ipq_errno = IPQ_ERR_HANDLE; 210 return NULL; 211 } 212 213 memset(h, 0, sizeof(struct ipq_handle)); 214 215 if (protocol == PF_INET) 216 h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_FIREWALL); 217 else if (protocol == PF_INET6) 218 h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_IP6_FW); 219 else { 220 ipq_errno = IPQ_ERR_PROTOCOL; 221 free(h); 222 return NULL; 223 } 224 225 if (h->fd == -1) { 226 ipq_errno = IPQ_ERR_SOCKET; 227 close(h->fd); 228 free(h); 229 return NULL; 230 } 231 memset(&h->local, 0, sizeof(struct sockaddr_nl)); 232 h->local.nl_family = AF_NETLINK; 233 h->local.nl_pid = getpid(); 234 h->local.nl_groups = 0; 235 status = bind(h->fd, (struct sockaddr *)&h->local, sizeof(h->local)); 236 if (status == -1) { 237 ipq_errno = IPQ_ERR_BIND; 238 close(h->fd); 239 free(h); 240 return NULL; 241 } 242 memset(&h->peer, 0, sizeof(struct sockaddr_nl)); 243 h->peer.nl_family = AF_NETLINK; 244 h->peer.nl_pid = 0; 245 h->peer.nl_groups = 0; 246 return h; 247} 248 249/* 250 * No error condition is checked here at this stage, but it may happen 251 * if/when reliable messaging is implemented. 252 */ 253int ipq_destroy_handle(struct ipq_handle *h) 254{ 255 if (h) { 256 close(h->fd); 257 free(h); 258 } 259 return 0; 260} 261 262int ipq_set_mode(const struct ipq_handle *h, 263 u_int8_t mode, size_t range) 264{ 265 struct { 266 struct nlmsghdr nlh; 267 ipq_peer_msg_t pm; 268 } req; 269 270 memset(&req, 0, sizeof(req)); 271 req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(req)); 272 req.nlh.nlmsg_flags = NLM_F_REQUEST; 273 req.nlh.nlmsg_type = IPQM_MODE; 274 req.nlh.nlmsg_pid = h->local.nl_pid; 275 req.pm.msg.mode.value = mode; 276 req.pm.msg.mode.range = range; 277 return ipq_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); 278} 279 280/* 281 * timeout is in microseconds (1 second is 1000000 (1 million) microseconds) 282 * 283 */ 284ssize_t ipq_read(const struct ipq_handle *h, 285 unsigned char *buf, size_t len, int timeout) 286{ 287 return ipq_netlink_recvfrom(h, buf, len, timeout); 288} 289 290int ipq_message_type(const unsigned char *buf) 291{ 292 return ((struct nlmsghdr*)buf)->nlmsg_type; 293} 294 295int ipq_get_msgerr(const unsigned char *buf) 296{ 297 struct nlmsghdr *h = (struct nlmsghdr *)buf; 298 struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h); 299 return -err->error; 300} 301 302ipq_packet_msg_t *ipq_get_packet(const unsigned char *buf) 303{ 304 return NLMSG_DATA((struct nlmsghdr *)(buf)); 305} 306 307int ipq_set_verdict(const struct ipq_handle *h, 308 ipq_id_t id, 309 unsigned int verdict, 310 size_t data_len, 311 unsigned char *buf) 312{ 313 unsigned char nvecs; 314 size_t tlen; 315 struct nlmsghdr nlh; 316 ipq_peer_msg_t pm; 317 struct iovec iov[3]; 318 struct msghdr msg; 319 320 memset(&nlh, 0, sizeof(nlh)); 321 nlh.nlmsg_flags = NLM_F_REQUEST; 322 nlh.nlmsg_type = IPQM_VERDICT; 323 nlh.nlmsg_pid = h->local.nl_pid; 324 memset(&pm, 0, sizeof(pm)); 325 pm.msg.verdict.value = verdict; 326 pm.msg.verdict.id = id; 327 pm.msg.verdict.data_len = data_len; 328 iov[0].iov_base = &nlh; 329 iov[0].iov_len = sizeof(nlh); 330 iov[1].iov_base = ± 331 iov[1].iov_len = sizeof(pm); 332 tlen = sizeof(nlh) + sizeof(pm); 333 nvecs = 2; 334 if (data_len && buf) { 335 iov[2].iov_base = buf; 336 iov[2].iov_len = data_len; 337 tlen += data_len; 338 nvecs++; 339 } 340 msg.msg_name = (void *)&h->peer; 341 msg.msg_namelen = sizeof(h->peer); 342 msg.msg_iov = iov; 343 msg.msg_iovlen = nvecs; 344 msg.msg_control = NULL; 345 msg.msg_controllen = 0; 346 msg.msg_flags = 0; 347 nlh.nlmsg_len = tlen; 348 return ipq_netlink_sendmsg(h, &msg, 0); 349} 350 351/* Not implemented yet */ 352int ipq_ctl(const struct ipq_handle *h, int request, ...) 353{ 354 return 1; 355} 356 357char *ipq_errstr(void) 358{ 359 return ipq_strerror(ipq_errno); 360} 361 362void ipq_perror(const char *s) 363{ 364 if (s) 365 fputs(s, stderr); 366 else 367 fputs("ERROR", stderr); 368 if (ipq_errno) 369 fprintf(stderr, ": %s", ipq_errstr()); 370 if (errno) 371 fprintf(stderr, ": %s", strerror(errno)); 372 fputc('\n', stderr); 373} 374