1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2021 Ng Peng Nam Sean 5 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/ck.h> 31 #include <sys/lock.h> 32 #include <sys/malloc.h> 33 #include <sys/mbuf.h> 34 #include <sys/mutex.h> 35 #include <sys/socket.h> 36 #include <sys/socketvar.h> 37 #include <sys/syslog.h> 38 39 #include <netlink/netlink.h> 40 #include <netlink/netlink_ctl.h> 41 #include <netlink/netlink_linux.h> 42 #include <netlink/netlink_var.h> 43 44 #define DEBUG_MOD_NAME nl_io 45 #define DEBUG_MAX_LEVEL LOG_DEBUG3 46 #include <netlink/netlink_debug.h> 47 _DECLARE_DEBUG(LOG_INFO); 48 49 /* 50 * The logic below provide a p2p interface for receiving and 51 * sending netlink data between the kernel and userland. 52 */ 53 54 static bool nl_process_nbuf(struct nl_buf *nb, struct nlpcb *nlp); 55 56 struct nl_buf * 57 nl_buf_alloc(size_t len, int mflag) 58 { 59 struct nl_buf *nb; 60 61 KASSERT(len > 0 && len <= UINT_MAX, ("%s: invalid length %zu", 62 __func__, len)); 63 64 nb = malloc(sizeof(struct nl_buf) + len, M_NETLINK, mflag); 65 if (__predict_true(nb != NULL)) { 66 nb->buflen = len; 67 nb->datalen = nb->offset = 0; 68 } 69 70 return (nb); 71 } 72 73 void 74 nl_buf_free(struct nl_buf *nb) 75 { 76 77 free(nb, M_NETLINK); 78 } 79 80 void 81 nl_schedule_taskqueue(struct nlpcb *nlp) 82 { 83 if (!nlp->nl_task_pending) { 84 nlp->nl_task_pending = true; 85 taskqueue_enqueue(nlp->nl_taskqueue, &nlp->nl_task); 86 NL_LOG(LOG_DEBUG3, "taskqueue scheduled"); 87 } else { 88 NL_LOG(LOG_DEBUG3, "taskqueue schedule skipped"); 89 } 90 } 91 92 static bool 93 nl_process_received_one(struct nlpcb *nlp) 94 { 95 struct socket *so = nlp->nl_socket; 96 struct sockbuf *sb; 97 struct nl_buf *nb; 98 bool reschedule = false; 99 100 NLP_LOCK(nlp); 101 nlp->nl_task_pending = false; 102 NLP_UNLOCK(nlp); 103 104 /* 105 * Do not process queued up requests if there is no space to queue 106 * replies. 107 */ 108 sb = &so->so_rcv; 109 SOCK_RECVBUF_LOCK(so); 110 if (sb->sb_hiwat <= sb->sb_ccc) { 111 SOCK_RECVBUF_UNLOCK(so); 112 NL_LOG(LOG_DEBUG3, "socket %p stuck", so); 113 return (false); 114 } 115 SOCK_RECVBUF_UNLOCK(so); 116 117 sb = &so->so_snd; 118 SOCK_SENDBUF_LOCK(so); 119 while ((nb = TAILQ_FIRST(&sb->nl_queue)) != NULL) { 120 TAILQ_REMOVE(&sb->nl_queue, nb, tailq); 121 SOCK_SENDBUF_UNLOCK(so); 122 reschedule = nl_process_nbuf(nb, nlp); 123 SOCK_SENDBUF_LOCK(so); 124 if (reschedule) { 125 sb->sb_acc -= nb->datalen; 126 sb->sb_ccc -= nb->datalen; 127 /* XXXGL: potentially can reduce lock&unlock count. */ 128 sowwakeup_locked(so); 129 nl_buf_free(nb); 130 SOCK_SENDBUF_LOCK(so); 131 } else { 132 TAILQ_INSERT_HEAD(&sb->nl_queue, nb, tailq); 133 break; 134 } 135 } 136 SOCK_SENDBUF_UNLOCK(so); 137 138 return (reschedule); 139 } 140 141 static void 142 nl_process_received(struct nlpcb *nlp) 143 { 144 NL_LOG(LOG_DEBUG3, "taskqueue called"); 145 146 if (__predict_false(nlp->nl_need_thread_setup)) { 147 nl_set_thread_nlp(curthread, nlp); 148 NLP_LOCK(nlp); 149 nlp->nl_need_thread_setup = false; 150 NLP_UNLOCK(nlp); 151 } 152 153 while (nl_process_received_one(nlp)) 154 ; 155 } 156 157 /* 158 * Called after some data have been read from the socket. 159 */ 160 void 161 nl_on_transmit(struct nlpcb *nlp) 162 { 163 NLP_LOCK(nlp); 164 165 struct socket *so = nlp->nl_socket; 166 if (__predict_false(nlp->nl_dropped_bytes > 0 && so != NULL)) { 167 unsigned long dropped_bytes = nlp->nl_dropped_bytes; 168 unsigned long dropped_messages = nlp->nl_dropped_messages; 169 nlp->nl_dropped_bytes = 0; 170 nlp->nl_dropped_messages = 0; 171 172 struct sockbuf *sb = &so->so_rcv; 173 NLP_LOG(LOG_DEBUG, nlp, 174 "socket RX overflowed, %lu messages (%lu bytes) dropped. " 175 "bytes: [%u/%u]", dropped_messages, dropped_bytes, 176 sb->sb_ccc, sb->sb_hiwat); 177 /* TODO: send netlink message */ 178 } 179 180 nl_schedule_taskqueue(nlp); 181 NLP_UNLOCK(nlp); 182 } 183 184 void 185 nl_taskqueue_handler(void *_arg, int pending) 186 { 187 struct nlpcb *nlp = (struct nlpcb *)_arg; 188 189 CURVNET_SET(nlp->nl_socket->so_vnet); 190 nl_process_received(nlp); 191 CURVNET_RESTORE(); 192 } 193 194 /* 195 * Tries to send current data buffer from writer. 196 * 197 * Returns true on success. 198 * If no queue overrunes happened, wakes up socket owner. 199 */ 200 bool 201 nl_send(struct nl_writer *nw, struct nlpcb *nlp) 202 { 203 struct socket *so = nlp->nl_socket; 204 struct sockbuf *sb = &so->so_rcv; 205 struct nl_buf *nb; 206 207 MPASS(nw->hdr == NULL); 208 MPASS(nw->buf != NULL); 209 MPASS(nw->buf->datalen > 0); 210 211 IF_DEBUG_LEVEL(LOG_DEBUG2) { 212 struct nlmsghdr *hdr = (struct nlmsghdr *)nw->buf->data; 213 NLP_LOG(LOG_DEBUG2, nlp, 214 "TX len %u msgs %u msg type %d first hdrlen %u", 215 nw->buf->datalen, nw->num_messages, hdr->nlmsg_type, 216 hdr->nlmsg_len); 217 } 218 219 if (nlp->nl_linux && linux_netlink_p != NULL && 220 __predict_false(!linux_netlink_p->msgs_to_linux(nw, nlp))) { 221 nl_buf_free(nw->buf); 222 nw->buf = NULL; 223 return (false); 224 } 225 226 nb = nw->buf; 227 nw->buf = NULL; 228 229 SOCK_RECVBUF_LOCK(so); 230 if (!nw->ignore_limit && __predict_false(sb->sb_hiwat <= sb->sb_ccc)) { 231 SOCK_RECVBUF_UNLOCK(so); 232 NLP_LOCK(nlp); 233 nlp->nl_dropped_bytes += nb->datalen; 234 nlp->nl_dropped_messages += nw->num_messages; 235 NLP_LOG(LOG_DEBUG2, nlp, "RX oveflow: %lu m (+%d), %lu b (+%d)", 236 (unsigned long)nlp->nl_dropped_messages, nw->num_messages, 237 (unsigned long)nlp->nl_dropped_bytes, nb->datalen); 238 NLP_UNLOCK(nlp); 239 nl_buf_free(nb); 240 return (false); 241 } else { 242 bool full; 243 244 TAILQ_INSERT_TAIL(&sb->nl_queue, nb, tailq); 245 sb->sb_acc += nb->datalen; 246 sb->sb_ccc += nb->datalen; 247 full = sb->sb_hiwat <= sb->sb_ccc; 248 sorwakeup_locked(so); 249 if (full) { 250 NLP_LOCK(nlp); 251 nlp->nl_tx_blocked = true; 252 NLP_UNLOCK(nlp); 253 } 254 return (true); 255 } 256 } 257 258 static int 259 nl_receive_message(struct nlmsghdr *hdr, int remaining_length, 260 struct nlpcb *nlp, struct nl_pstate *npt) 261 { 262 nl_handler_f handler = nl_handlers[nlp->nl_proto].cb; 263 int error = 0; 264 265 NLP_LOG(LOG_DEBUG2, nlp, "msg len: %u type: %d: flags: 0x%X seq: %u pid: %u", 266 hdr->nlmsg_len, hdr->nlmsg_type, hdr->nlmsg_flags, hdr->nlmsg_seq, 267 hdr->nlmsg_pid); 268 269 if (__predict_false(hdr->nlmsg_len > remaining_length)) { 270 NLP_LOG(LOG_DEBUG, nlp, "message is not entirely present: want %d got %d", 271 hdr->nlmsg_len, remaining_length); 272 return (EINVAL); 273 } else if (__predict_false(hdr->nlmsg_len < sizeof(*hdr))) { 274 NL_LOG(LOG_DEBUG, "message too short: %d", hdr->nlmsg_len); 275 return (EINVAL); 276 } 277 /* Stamp each message with sender pid */ 278 hdr->nlmsg_pid = nlp->nl_port; 279 280 npt->hdr = hdr; 281 282 if (hdr->nlmsg_flags & NLM_F_REQUEST && 283 hdr->nlmsg_type >= NLMSG_MIN_TYPE) { 284 NL_LOG(LOG_DEBUG2, "handling message with msg type: %d", 285 hdr->nlmsg_type); 286 if (nlp->nl_linux) { 287 MPASS(linux_netlink_p != NULL); 288 error = linux_netlink_p->msg_from_linux(nlp->nl_proto, 289 &hdr, npt); 290 if (error) 291 goto ack; 292 } 293 error = handler(hdr, npt); 294 NL_LOG(LOG_DEBUG2, "retcode: %d", error); 295 } 296 ack: 297 if ((hdr->nlmsg_flags & NLM_F_ACK) || (error != 0 && error != EINTR)) { 298 if (!npt->nw->suppress_ack) { 299 NL_LOG(LOG_DEBUG3, "ack"); 300 nlmsg_ack(nlp, error, hdr, npt); 301 } 302 } 303 304 return (0); 305 } 306 307 static void 308 npt_clear(struct nl_pstate *npt) 309 { 310 lb_clear(&npt->lb); 311 npt->error = 0; 312 npt->err_msg = NULL; 313 npt->err_off = 0; 314 npt->hdr = NULL; 315 npt->nw->suppress_ack = false; 316 } 317 318 /* 319 * Processes an incoming packet, which can contain multiple netlink messages 320 */ 321 static bool 322 nl_process_nbuf(struct nl_buf *nb, struct nlpcb *nlp) 323 { 324 struct nl_writer nw; 325 struct nlmsghdr *hdr; 326 int error; 327 328 NL_LOG(LOG_DEBUG3, "RX netlink buf %p on %p", nb, nlp->nl_socket); 329 330 if (!nl_writer_unicast(&nw, NLMSG_SMALL, nlp, false)) { 331 NL_LOG(LOG_DEBUG, "error allocating socket writer"); 332 return (true); 333 } 334 335 nlmsg_ignore_limit(&nw); 336 337 struct nl_pstate npt = { 338 .nlp = nlp, 339 .lb.base = &nb->data[roundup2(nb->datalen, 8)], 340 .lb.size = nb->buflen - roundup2(nb->datalen, 8), 341 .nw = &nw, 342 .strict = nlp->nl_flags & NLF_STRICT, 343 }; 344 345 for (; nb->offset + sizeof(struct nlmsghdr) <= nb->datalen;) { 346 hdr = (struct nlmsghdr *)&nb->data[nb->offset]; 347 /* Save length prior to calling handler */ 348 int msglen = NLMSG_ALIGN(hdr->nlmsg_len); 349 NL_LOG(LOG_DEBUG3, "parsing offset %d/%d", 350 nb->offset, nb->datalen); 351 npt_clear(&npt); 352 error = nl_receive_message(hdr, nb->datalen - nb->offset, nlp, 353 &npt); 354 nb->offset += msglen; 355 if (__predict_false(error != 0 || nlp->nl_tx_blocked)) 356 break; 357 } 358 NL_LOG(LOG_DEBUG3, "packet parsing done"); 359 nlmsg_flush(&nw); 360 361 if (nlp->nl_tx_blocked) { 362 NLP_LOCK(nlp); 363 nlp->nl_tx_blocked = false; 364 NLP_UNLOCK(nlp); 365 return (false); 366 } else 367 return (true); 368 } 369