sd-netlink: message - split up source file

Split netlink-socket.c and rtnl-message.c from netlink-message.c.

1 files changed, 275 insertions, 0 deletions

diff --git a/src/libsystemd/sd-netlink/netlink-socket.c b/src/libsystemd/sd-netlink/netlink-socket.c
new file mode 100644
index 0000000000..2e2826ac63
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-socket.c
@@ -0,0 +1,275 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Tom Gundersen <teg@jklm.no>
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <netinet/in.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "util.h"
+#include "socket-util.h"
+#include "formats-util.h"
+#include "refcnt.h"
+#include "missing.h"
+
+#include "sd-netlink.h"
+#include "netlink-util.h"
+#include "netlink-internal.h"
+#include "netlink-types.h"
+
+/* returns the number of bytes sent, or a negative error code */
+int socket_write_message(sd_netlink *nl, sd_netlink_message *m) {
+        union {
+                struct sockaddr sa;
+                struct sockaddr_nl nl;
+        } addr = {
+                .nl.nl_family = AF_NETLINK,
+        };
+        ssize_t k;
+
+        assert(nl);
+        assert(m);
+        assert(m->hdr);
+
+        k = sendto(nl->fd, m->hdr, m->hdr->nlmsg_len,
+                        0, &addr.sa, sizeof(addr));
+        if (k < 0)
+                return -errno;
+
+        return k;
+}
+
+static int socket_recv_message(int fd, struct iovec *iov, uint32_t *_group, bool peek) {
+        union sockaddr_union sender;
+        uint8_t cmsg_buffer[CMSG_SPACE(sizeof(struct nl_pktinfo))];
+        struct msghdr msg = {
+                .msg_iov = iov,
+                .msg_iovlen = 1,
+                .msg_name = &sender,
+                .msg_namelen = sizeof(sender),
+                .msg_control = cmsg_buffer,
+                .msg_controllen = sizeof(cmsg_buffer),
+        };
+        struct cmsghdr *cmsg;
+        uint32_t group = 0;
+        int r;
+
+        assert(fd >= 0);
+        assert(iov);
+
+        r = recvmsg(fd, &msg, MSG_TRUNC | (peek ? MSG_PEEK : 0));
+        if (r < 0) {
+                /* no data */
+                if (errno == ENOBUFS)
+                        log_debug("rtnl: kernel receive buffer overrun");
+                else if (errno == EAGAIN)
+                        log_debug("rtnl: no data in socket");
+
+                return (errno == EAGAIN || errno == EINTR) ? 0 : -errno;
+        }
+
+        if (sender.nl.nl_pid != 0) {
+                /* not from the kernel, ignore */
+                log_debug("rtnl: ignoring message from portid %"PRIu32, sender.nl.nl_pid);
+
+                if (peek) {
+                        /* drop the message */
+                        r = recvmsg(fd, &msg, 0);
+                        if (r < 0)
+                                return (errno == EAGAIN || errno == EINTR) ? 0 : -errno;
+                }
+
+                return 0;
+        }
+
+        CMSG_FOREACH(cmsg, &msg) {
+                if (cmsg->cmsg_level == SOL_NETLINK &&
+                    cmsg->cmsg_type == NETLINK_PKTINFO &&
+                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct nl_pktinfo))) {
+                        struct nl_pktinfo *pktinfo = (void *)CMSG_DATA(cmsg);
+
+                        /* multi-cast group */
+                        group = pktinfo->group;
+                }
+        }
+
+        if (_group)
+                *_group = group;
+
+        return r;
+}
+
+/* On success, the number of bytes received is returned and *ret points to the received message
+ * which has a valid header and the correct size.
+ * If nothing useful was received 0 is returned.
+ * On failure, a negative error code is returned.
+ */
+int socket_read_message(sd_netlink *rtnl) {
+        _cleanup_netlink_message_unref_ sd_netlink_message *first = NULL;
+        struct iovec iov = {};
+        uint32_t group = 0;
+        bool multi_part = false, done = false;
+        struct nlmsghdr *new_msg;
+        size_t len;
+        int r;
+        unsigned i = 0;
+
+        assert(rtnl);
+        assert(rtnl->rbuffer);
+        assert(rtnl->rbuffer_allocated >= sizeof(struct nlmsghdr));
+
+        /* read nothing, just get the pending message size */
+        r = socket_recv_message(rtnl->fd, &iov, NULL, true);
+        if (r <= 0)
+                return r;
+        else
+                len = (size_t)r;
+
+        /* make room for the pending message */
+        if (!greedy_realloc((void **)&rtnl->rbuffer,
+                            &rtnl->rbuffer_allocated,
+                            len, sizeof(uint8_t)))
+                return -ENOMEM;
+
+        iov.iov_base = rtnl->rbuffer;
+        iov.iov_len = rtnl->rbuffer_allocated;
+
+        /* read the pending message */
+        r = socket_recv_message(rtnl->fd, &iov, &group, false);
+        if (r <= 0)
+                return r;
+        else
+                len = (size_t)r;
+
+        if (len > rtnl->rbuffer_allocated)
+                /* message did not fit in read buffer */
+                return -EIO;
+
+        if (NLMSG_OK(rtnl->rbuffer, len) && rtnl->rbuffer->nlmsg_flags & NLM_F_MULTI) {
+                multi_part = true;
+
+                for (i = 0; i < rtnl->rqueue_partial_size; i++) {
+                        if (rtnl_message_get_serial(rtnl->rqueue_partial[i]) ==
+                            rtnl->rbuffer->nlmsg_seq) {
+                                first = rtnl->rqueue_partial[i];
+                                break;
+                        }
+                }
+        }
+
+        for (new_msg = rtnl->rbuffer; NLMSG_OK(new_msg, len) && !done; new_msg = NLMSG_NEXT(new_msg, len)) {
+                _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+                const NLType *nl_type;
+
+                if (!group && new_msg->nlmsg_pid != rtnl->sockaddr.nl.nl_pid)
+                        /* not broadcast and not for us */
+                        continue;
+
+                if (new_msg->nlmsg_type == NLMSG_NOOP)
+                        /* silently drop noop messages */
+                        continue;
+
+                if (new_msg->nlmsg_type == NLMSG_DONE) {
+                        /* finished reading multi-part message */
+                        done = true;
+
+                        /* if first is not defined, put NLMSG_DONE into the receive queue. */
+                        if (first)
+                                continue;
+                }
+
+                /* check that we support this message type */
+                r = type_system_get_type(NULL, &nl_type, new_msg->nlmsg_type);
+                if (r < 0) {
+                        if (r == -EOPNOTSUPP)
+                                log_debug("sd-netlink: ignored message with unknown type: %i",
+                                          new_msg->nlmsg_type);
+
+                        continue;
+                }
+
+                /* check that the size matches the message type */
+                if (new_msg->nlmsg_len < NLMSG_LENGTH(nl_type->size)) {
+                        log_debug("sd-netlink: message larger than expected, dropping");
+                        continue;
+                }
+
+                r = message_new_empty(rtnl, &m);
+                if (r < 0)
+                        return r;
+
+                m->broadcast = !!group;
+
+                m->hdr = memdup(new_msg, new_msg->nlmsg_len);
+                if (!m->hdr)
+                        return -ENOMEM;
+
+                /* seal and parse the top-level message */
+                r = sd_netlink_message_rewind(m);
+                if (r < 0)
+                        return r;
+
+                /* push the message onto the multi-part message stack */
+                if (first)
+                        m->next = first;
+                first = m;
+                m = NULL;
+        }
+
+        if (len)
+                log_debug("sd-netlink: discarding %zu bytes of incoming message", len);
+
+        if (!first)
+                return 0;
+
+        if (!multi_part || done) {
+                /* we got a complete message, push it on the read queue */
+                r = rtnl_rqueue_make_room(rtnl);
+                if (r < 0)
+                        return r;
+
+                rtnl->rqueue[rtnl->rqueue_size ++] = first;
+                first = NULL;
+
+                if (multi_part && (i < rtnl->rqueue_partial_size)) {
+                        /* remove the message form the partial read queue */
+                        memmove(rtnl->rqueue_partial + i,rtnl->rqueue_partial + i + 1,
+                                sizeof(sd_netlink_message*) * (rtnl->rqueue_partial_size - i - 1));
+                        rtnl->rqueue_partial_size --;
+                }
+
+                return 1;
+        } else {
+                /* we only got a partial multi-part message, push it on the
+                   partial read queue */
+                if (i < rtnl->rqueue_partial_size) {
+                        rtnl->rqueue_partial[i] = first;
+                } else {
+                        r = rtnl_rqueue_partial_make_room(rtnl);
+                        if (r < 0)
+                                return r;
+
+                        rtnl->rqueue_partial[rtnl->rqueue_partial_size ++] = first;
+                }
+                first = NULL;
+
+                return 0;
+        }
+}