341 lines
11 KiB
C
341 lines
11 KiB
C
/* (C) 2011 by Pablo Neira Ayuso <pablo@gnumonks.org>
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* (C) 2015-2016 by Harald Welte <laforge@gnumonks.org>
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* (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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* All Rights Reserved.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <time.h>
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#include <sys/fcntl.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <netinet/tcp.h>
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#include <osmocom/core/timer.h>
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#include <osmocom/core/select.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/gsm/tlv.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/osmo_io.h>
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#include <osmocom/core/panic.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/core/talloc.h>
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#include <osmocom/core/socket.h>
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#include <osmocom/netif/stream.h>
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#include <osmocom/netif/stream_private.h>
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#include "config.h"
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#include <osmocom/netif/sctp.h>
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/*! \cond private */
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#ifdef HAVE_LIBSCTP
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/* is any of the bytes from offset .. u8_size in 'u8' non-zero? return offset or -1 if all zero */
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static int byte_nonzero(const uint8_t *u8, unsigned int offset, unsigned int u8_size)
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{
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int j;
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for (j = offset; j < u8_size; j++) {
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if (u8[j] != 0)
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return j;
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}
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return -1;
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}
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static unsigned int sctp_sockopt_event_subscribe_size = 0;
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static int determine_sctp_sockopt_event_subscribe_size(void)
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{
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uint8_t buf[256];
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socklen_t buf_len = sizeof(buf);
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int sd, rc;
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/* only do this once */
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if (sctp_sockopt_event_subscribe_size > 0)
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return 0;
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sd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
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if (sd < 0)
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return sd;
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rc = getsockopt(sd, IPPROTO_SCTP, SCTP_EVENTS, buf, &buf_len);
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close(sd);
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if (rc < 0)
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return rc;
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sctp_sockopt_event_subscribe_size = (unsigned int)buf_len;
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LOGP(DLINP, LOGL_INFO, "sizes of 'struct sctp_event_subscribe': compile-time %zu, kernel: %u\n",
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sizeof(struct sctp_event_subscribe), sctp_sockopt_event_subscribe_size);
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return 0;
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}
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/* Attempt to work around Linux kernel ABI breakage
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*
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* The Linux kernel ABI for the SCTP_EVENTS socket option has been broken repeatedly.
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* - until commit 35ea82d611da59f8bea44a37996b3b11bb1d3fd7 ( kernel < 4.11), the size is 10 bytes
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* - in 4.11 it is 11 bytes
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* - in 4.12 .. 5.4 it is 13 bytes
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* - in kernels >= 5.5 it is 14 bytes
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*
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* This wouldn't be a problem if the kernel didn't have a "stupid" assumption that the structure
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* size passed by userspace will match 1:1 the length of the structure at kernel compile time. In
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* an ideal world, it would just use the known first bytes and assume the remainder is all zero.
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* But as it doesn't do that, let's try to work around this */
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static int sctp_setsockopt_events_linux_workaround(int fd, const struct sctp_event_subscribe *event)
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{
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const unsigned int compiletime_size = sizeof(*event);
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int rc;
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if (determine_sctp_sockopt_event_subscribe_size() < 0) {
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LOGP(DLINP, LOGL_ERROR, "Cannot determine SCTP_EVENTS socket option size\n");
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return -1;
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}
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if (compiletime_size == sctp_sockopt_event_subscribe_size) {
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/* no kernel workaround needed */
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return setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, event, compiletime_size);
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} else if (compiletime_size < sctp_sockopt_event_subscribe_size) {
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/* we are using an older userspace with a more modern kernel and hence need
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* to pad the data */
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uint8_t buf[sctp_sockopt_event_subscribe_size];
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memcpy(buf, event, compiletime_size);
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memset(buf + sizeof(*event), 0, sctp_sockopt_event_subscribe_size - compiletime_size);
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return setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, buf, sctp_sockopt_event_subscribe_size);
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} else /* if (compiletime_size > sctp_sockopt_event_subscribe_size) */ {
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/* we are using a newer userspace with an older kernel and hence need to truncate
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* the data - but only if the caller didn't try to enable any of the events of the
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* truncated portion */
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rc = byte_nonzero((const uint8_t *)event, sctp_sockopt_event_subscribe_size,
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compiletime_size);
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if (rc >= 0) {
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LOGP(DLINP, LOGL_ERROR, "Kernel only supports sctp_event_subscribe of %u bytes, "
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"but caller tried to enable more modern event at offset %u\n",
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sctp_sockopt_event_subscribe_size, rc);
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return -1;
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}
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return setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, event, sctp_sockopt_event_subscribe_size);
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}
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}
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#endif // HAVE_LIBSCTP
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int stream_sctp_sock_activate_events(int fd)
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{
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#ifdef HAVE_LIBSCTP
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struct sctp_event_subscribe event;
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int rc;
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/* subscribe for all relevant events */
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memset((uint8_t *)&event, 0, sizeof(event));
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event.sctp_data_io_event = 1;
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event.sctp_association_event = 1;
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event.sctp_address_event = 1;
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event.sctp_send_failure_event = 1;
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event.sctp_peer_error_event = 1;
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event.sctp_shutdown_event = 1;
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/* IMPORTANT: Do NOT enable sender_dry_event here, see
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* https://bugzilla.redhat.com/show_bug.cgi?id=1442784 */
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rc = sctp_setsockopt_events_linux_workaround(fd, &event);
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if (rc < 0)
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LOGP(DLINP, LOGL_ERROR, "couldn't activate SCTP events on FD %u\n", fd);
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return rc;
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#else
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return -1;
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#endif
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}
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int stream_setsockopt_nodelay(int fd, int proto, int on)
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{
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int rc;
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switch (proto) {
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#ifdef HAVE_LIBSCTP
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case IPPROTO_SCTP:
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rc = setsockopt(fd, IPPROTO_SCTP, SCTP_NODELAY, &on, sizeof(on));
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break;
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#endif
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case IPPROTO_TCP:
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rc = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
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break;
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default:
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rc = -1;
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LOGP(DLINP, LOGL_ERROR, "Unknown protocol %u, cannot set NODELAY\n",
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proto);
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break;
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}
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return rc;
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}
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#ifdef HAVE_LIBSCTP
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static int stream_sctp_recvmsg_trailer(const char *log_pfx, struct msgb *msg, int ret, const struct sctp_sndrcvinfo *sinfo, int flags)
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{
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msgb_sctp_msg_flags(msg) = 0;
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if (OSMO_LIKELY(sinfo)) {
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msgb_sctp_ppid(msg) = ntohl(sinfo->sinfo_ppid);
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msgb_sctp_stream(msg) = sinfo->sinfo_stream;
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}
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if (flags & MSG_NOTIFICATION) {
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char buf[512];
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struct osmo_strbuf sb = { .buf = buf, .len = sizeof(buf) };
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int logl = LOGL_INFO;
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union sctp_notification *notif = (union sctp_notification *) msg->data;
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OSMO_STRBUF_PRINTF(sb, "%s NOTIFICATION %s flags=0x%x", log_pfx,
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osmo_sctp_sn_type_str(notif->sn_header.sn_type), notif->sn_header.sn_flags);
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msgb_put(msg, sizeof(union sctp_notification));
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msgb_sctp_msg_flags(msg) = OSMO_STREAM_SCTP_MSG_FLAGS_NOTIFICATION;
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ret = -EAGAIN;
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switch (notif->sn_header.sn_type) {
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case SCTP_ASSOC_CHANGE:
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OSMO_STRBUF_PRINTF(sb, " %s", osmo_sctp_assoc_chg_str(notif->sn_assoc_change.sac_state));
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switch (notif->sn_assoc_change.sac_state) {
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case SCTP_COMM_UP:
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break;
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case SCTP_COMM_LOST:
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OSMO_STRBUF_PRINTF(sb, " (err: %s)",
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osmo_sctp_sn_error_str(notif->sn_assoc_change.sac_error));
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/* Handle this like a regular disconnect */
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ret = 0;
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break;
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case SCTP_RESTART:
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case SCTP_SHUTDOWN_COMP:
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logl = LOGL_NOTICE;
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break;
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case SCTP_CANT_STR_ASSOC:
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break;
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}
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break;
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case SCTP_SEND_FAILED:
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logl = LOGL_ERROR;
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break;
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case SCTP_PEER_ADDR_CHANGE:
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{
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char addr_str[INET6_ADDRSTRLEN + 10];
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struct sockaddr_storage sa = notif->sn_paddr_change.spc_aaddr;
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osmo_sockaddr_to_str_buf(addr_str, sizeof(addr_str),
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(const struct osmo_sockaddr *)&sa);
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OSMO_STRBUF_PRINTF(sb, " %s %s err=%s",
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osmo_sctp_paddr_chg_str(notif->sn_paddr_change.spc_state), addr_str,
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(notif->sn_paddr_change.spc_state == SCTP_ADDR_UNREACHABLE) ?
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osmo_sctp_sn_error_str(notif->sn_paddr_change.spc_error) : "None");
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}
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break;
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case SCTP_SHUTDOWN_EVENT:
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logl = LOGL_NOTICE;
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/* RFC6458 3.1.4: Any attempt to send more data will cause sendmsg()
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* to return with an ESHUTDOWN error. */
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break;
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case SCTP_REMOTE_ERROR:
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logl = LOGL_NOTICE;
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OSMO_STRBUF_PRINTF(sb, " %s", osmo_sctp_op_error_str(ntohs(notif->sn_remote_error.sre_error)));
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break;
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}
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LOGP(DLINP, logl, "%s\n", buf);
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return ret;
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}
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if (OSMO_UNLIKELY(ret > 0 && !sinfo))
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LOGP(DLINP, LOGL_ERROR, "%s sctp_recvmsg without SNDRCV cmsg?!?\n", log_pfx);
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return ret;
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}
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/*! wrapper for regular synchronous sctp_recvmsg(3) */
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int stream_sctp_recvmsg_wrapper(int fd, struct msgb *msg, const char *log_pfx)
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{
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struct sctp_sndrcvinfo sinfo;
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int flags = 0;
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int ret;
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ret = sctp_recvmsg(fd, msg->tail, msgb_tailroom(msg), NULL, NULL, &sinfo, &flags);
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return stream_sctp_recvmsg_trailer(log_pfx, msg, ret, &sinfo, flags);
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}
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/*! wrapper for osmo_io asynchronous recvmsg response */
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int stream_iofd_sctp_recvmsg_trailer(struct osmo_io_fd *iofd, struct msgb *msg, int ret, const struct msghdr *msgh)
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{
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const struct sctp_sndrcvinfo *sinfo = NULL;
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struct cmsghdr *cmsg = NULL;
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for (cmsg = CMSG_FIRSTHDR((struct msghdr *) msgh); cmsg != NULL;
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cmsg = CMSG_NXTHDR((struct msghdr *) msgh, cmsg)) {
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if (cmsg->cmsg_level == IPPROTO_SCTP && cmsg->cmsg_type == SCTP_SNDRCV) {
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sinfo = (const struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
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break;
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}
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}
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return stream_sctp_recvmsg_trailer(osmo_iofd_get_name(iofd), msg, ret, sinfo, msgh->msg_flags);
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}
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/*! Send a message through a connected SCTP socket, similar to sctp_sendmsg().
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*
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* Appends the message to the internal transmit queue.
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* If the function returns success (0), it will take ownership of the msgb and
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* internally call msgb_free() after the write request completes.
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* In case of an error the msgb needs to be freed by the caller.
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*
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* \param[in] iofd file descriptor to write to
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* \param[in] msg message buffer to send; uses msgb_sctp_ppid/msg_sctp_stream
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* \param[in] sendmsg_flags Flags to pass to the send call
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* \returns 0 in case of success; a negative value in case of error
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*/
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int stream_iofd_sctp_send_msgb(struct osmo_io_fd *iofd, struct msgb *msg, int sendmsg_flags)
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{
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struct msghdr outmsg = {};
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char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
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struct sctp_sndrcvinfo *sinfo;
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struct cmsghdr *cmsg;
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outmsg.msg_control = outcmsg;
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outmsg.msg_controllen = sizeof(outcmsg);
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cmsg = CMSG_FIRSTHDR(&outmsg);
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cmsg->cmsg_level = IPPROTO_SCTP;
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cmsg->cmsg_type = SCTP_SNDRCV;
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cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
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outmsg.msg_controllen = cmsg->cmsg_len;
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sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
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memset(sinfo, 0, sizeof(struct sctp_sndrcvinfo));
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sinfo->sinfo_ppid = htonl(msgb_sctp_ppid(msg));
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sinfo->sinfo_stream = msgb_sctp_stream(msg);
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return osmo_iofd_sendmsg_msgb(iofd, msg, sendmsg_flags, &outmsg);
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}
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#endif
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/*! \endccond */
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