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authorDavid Herrmann <dh.herrmann@googlemail.com>2015-10-16 13:05:39 +0200
committerDavid Herrmann <dh.herrmann@googlemail.com>2015-10-16 13:05:39 +0200
commit7a1e5abbc6e741e5b6995288c607522faa69c8b4 (patch)
tree2fd03f08cb9aa275e1846c1aa9e24aa8ec615e3d
parent8ee07361d0065a2d4ab9c4bf6aeb0893b05b2b6c (diff)
parent9c5a882b7fc256ddc0b227677fa06546f0e944a8 (diff)
Merge pull request #1581 from teg/netlink-broadcast-leave
sd-netlink: refcount multicast groups
-rw-r--r--src/basic/missing.h4
-rw-r--r--src/libsystemd/sd-netlink/netlink-internal.h6
-rw-r--r--src/libsystemd/sd-netlink/netlink-socket.c155
-rw-r--r--src/libsystemd/sd-netlink/sd-netlink.c56
4 files changed, 205 insertions, 16 deletions
diff --git a/src/basic/missing.h b/src/basic/missing.h
index 59e835a466..5fb9951a84 100644
--- a/src/basic/missing.h
+++ b/src/basic/missing.h
@@ -126,6 +126,10 @@
#define SOL_NETLINK 270
#endif
+#ifndef NETLINK_LIST_MEMBERSHIPS
+#define NETLINK_LIST_MEMBERSHIPS 9
+#endif
+
#if !HAVE_DECL_PIVOT_ROOT
static inline int pivot_root(const char *new_root, const char *put_old) {
return syscall(SYS_pivot_root, new_root, put_old);
diff --git a/src/libsystemd/sd-netlink/netlink-internal.h b/src/libsystemd/sd-netlink/netlink-internal.h
index 4026e2c341..b9cb80668d 100644
--- a/src/libsystemd/sd-netlink/netlink-internal.h
+++ b/src/libsystemd/sd-netlink/netlink-internal.h
@@ -64,6 +64,9 @@ struct sd_netlink {
struct sockaddr_nl nl;
} sockaddr;
+ Hashmap *broadcast_group_refs;
+ bool broadcast_group_dont_leave:1; /* until we can rely on 4.2 */
+
sd_netlink_message **rqueue;
unsigned rqueue_size;
size_t rqueue_allocated;
@@ -124,7 +127,8 @@ int message_new_empty(sd_netlink *rtnl, sd_netlink_message **ret);
int socket_open(int family);
int socket_bind(sd_netlink *nl);
-int socket_join_broadcast_group(sd_netlink *nl, unsigned group);
+int socket_broadcast_group_ref(sd_netlink *nl, unsigned group);
+int socket_broadcast_group_unref(sd_netlink *nl, unsigned group);
int socket_write_message(sd_netlink *nl, sd_netlink_message *m);
int socket_read_message(sd_netlink *nl);
diff --git a/src/libsystemd/sd-netlink/netlink-socket.c b/src/libsystemd/sd-netlink/netlink-socket.c
index 84ff7c38c9..e1b14c3ed2 100644
--- a/src/libsystemd/sd-netlink/netlink-socket.c
+++ b/src/libsystemd/sd-netlink/netlink-socket.c
@@ -44,6 +44,65 @@ int socket_open(int family) {
return fd;
}
+static int broadcast_groups_get(sd_netlink *nl) {
+ _cleanup_free_ uint32_t *groups = NULL;
+ socklen_t len = 0, old_len;
+ unsigned i, j;
+ int r;
+
+ assert(nl);
+ assert(nl->fd > 0);
+
+ r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, NULL, &len);
+ if (r < 0) {
+ if (errno == ENOPROTOOPT) {
+ nl->broadcast_group_dont_leave = true;
+ return 0;
+ } else
+ return -errno;
+ }
+
+ if (len == 0)
+ return 0;
+
+ groups = new0(uint32_t, len);
+ if (!groups)
+ return -ENOMEM;
+
+ old_len = len;
+
+ r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, groups, &len);
+ if (r < 0)
+ return -errno;
+
+ if (old_len != len)
+ return -EIO;
+
+ r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL);
+ if (r < 0)
+ return r;
+
+ for (i = 0; i < len; i++) {
+ for (j = 0; j < sizeof(uint32_t) * 8; j ++) {
+ uint32_t offset;
+ unsigned group;
+
+ offset = 1U << j;
+
+ if (!(groups[i] & offset))
+ continue;
+
+ group = i * sizeof(uint32_t) * 8 + j + 1;
+
+ r = hashmap_put(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(1));
+ if (r < 0)
+ return r;
+ }
+ }
+
+ return 0;
+}
+
int socket_bind(sd_netlink *nl) {
socklen_t addrlen;
int r, one = 1;
@@ -63,11 +122,32 @@ int socket_bind(sd_netlink *nl) {
if (r < 0)
return -errno;
+ r = broadcast_groups_get(nl);
+ if (r < 0)
+ return r;
+
return 0;
}
+static unsigned broadcast_group_get_ref(sd_netlink *nl, unsigned group) {
+ assert(nl);
+
+ return PTR_TO_UINT(hashmap_get(nl->broadcast_group_refs, UINT_TO_PTR(group)));
+}
-int socket_join_broadcast_group(sd_netlink *nl, unsigned group) {
+static int broadcast_group_set_ref(sd_netlink *nl, unsigned group, unsigned n_ref) {
+ int r;
+
+ assert(nl);
+
+ r = hashmap_replace(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(n_ref));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int broadcast_group_join(sd_netlink *nl, unsigned group) {
int r;
assert(nl);
@@ -81,6 +161,79 @@ int socket_join_broadcast_group(sd_netlink *nl, unsigned group) {
return 0;
}
+int socket_broadcast_group_ref(sd_netlink *nl, unsigned group) {
+ unsigned n_ref;
+ int r;
+
+ assert(nl);
+
+ n_ref = broadcast_group_get_ref(nl, group);
+
+ n_ref ++;
+
+ r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL);
+ if (r < 0)
+ return r;
+
+ r = broadcast_group_set_ref(nl, group, n_ref);
+ if (r < 0)
+ return r;
+
+ if (n_ref > 1)
+ /* not yet in the group */
+ return 0;
+
+ r = broadcast_group_join(nl, group);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int broadcast_group_leave(sd_netlink *nl, unsigned group) {
+ int r;
+
+ assert(nl);
+ assert(nl->fd >= 0);
+ assert(group > 0);
+
+ if (nl->broadcast_group_dont_leave)
+ return 0;
+
+ r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, &group, sizeof(group));
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
+
+int socket_broadcast_group_unref(sd_netlink *nl, unsigned group) {
+ unsigned n_ref;
+ int r;
+
+ assert(nl);
+
+ n_ref = broadcast_group_get_ref(nl, group);
+
+ assert(n_ref > 0);
+
+ n_ref --;
+
+ r = broadcast_group_set_ref(nl, group, n_ref);
+ if (r < 0)
+ return r;
+
+ if (n_ref > 0)
+ /* still refs left */
+ return 0;
+
+ r = broadcast_group_leave(nl, group);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
/* returns the number of bytes sent, or a negative error code */
int socket_write_message(sd_netlink *nl, sd_netlink_message *m) {
union {
diff --git a/src/libsystemd/sd-netlink/sd-netlink.c b/src/libsystemd/sd-netlink/sd-netlink.c
index f4a0a358a9..5af28600ba 100644
--- a/src/libsystemd/sd-netlink/sd-netlink.c
+++ b/src/libsystemd/sd-netlink/sd-netlink.c
@@ -183,10 +183,11 @@ sd_netlink *sd_netlink_unref(sd_netlink *rtnl) {
sd_event_unref(rtnl->event);
while ((f = rtnl->match_callbacks)) {
- LIST_REMOVE(match_callbacks, rtnl->match_callbacks, f);
- free(f);
+ sd_netlink_remove_match(rtnl, f->type, f->callback, f->userdata);
}
+ hashmap_free(rtnl->broadcast_group_refs);
+
safe_close(rtnl->fd);
free(rtnl);
}
@@ -857,29 +858,29 @@ int sd_netlink_add_match(sd_netlink *rtnl,
switch (type) {
case RTM_NEWLINK:
case RTM_DELLINK:
- r = socket_join_broadcast_group(rtnl, RTNLGRP_LINK);
+ r = socket_broadcast_group_ref(rtnl, RTNLGRP_LINK);
if (r < 0)
return r;
break;
case RTM_NEWADDR:
case RTM_DELADDR:
- r = socket_join_broadcast_group(rtnl, RTNLGRP_IPV4_IFADDR);
+ r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV4_IFADDR);
if (r < 0)
return r;
- r = socket_join_broadcast_group(rtnl, RTNLGRP_IPV6_IFADDR);
+ r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV6_IFADDR);
if (r < 0)
return r;
break;
case RTM_NEWROUTE:
case RTM_DELROUTE:
- r = socket_join_broadcast_group(rtnl, RTNLGRP_IPV4_ROUTE);
+ r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV4_ROUTE);
if (r < 0)
return r;
- r = socket_join_broadcast_group(rtnl, RTNLGRP_IPV6_ROUTE);
+ r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV6_ROUTE);
if (r < 0)
return r;
break;
@@ -899,23 +900,50 @@ int sd_netlink_remove_match(sd_netlink *rtnl,
sd_netlink_message_handler_t callback,
void *userdata) {
struct match_callback *c;
+ int r;
assert_return(rtnl, -EINVAL);
assert_return(callback, -EINVAL);
assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
- /* we should unsubscribe from the broadcast groups at this point, but it is not so
- trivial for a few reasons: the refcounting is a bit of a mess and not obvious
- how it will look like after we add genetlink support, and it is also not possible
- to query what broadcast groups were subscribed to when we inherit the socket to get
- the initial refcount. The latter could indeed be done for the first 32 broadcast
- groups (which incidentally is all we currently support in .socket units anyway),
- but we better not rely on only ever using 32 groups. */
LIST_FOREACH(match_callbacks, c, rtnl->match_callbacks)
if (c->callback == callback && c->type == type && c->userdata == userdata) {
LIST_REMOVE(match_callbacks, rtnl->match_callbacks, c);
free(c);
+ switch (type) {
+ case RTM_NEWLINK:
+ case RTM_DELLINK:
+ r = socket_broadcast_group_unref(rtnl, RTNLGRP_LINK);
+ if (r < 0)
+ return r;
+
+ break;
+ case RTM_NEWADDR:
+ case RTM_DELADDR:
+ r = socket_broadcast_group_unref(rtnl, RTNLGRP_IPV4_IFADDR);
+ if (r < 0)
+ return r;
+
+ r = socket_broadcast_group_unref(rtnl, RTNLGRP_IPV6_IFADDR);
+ if (r < 0)
+ return r;
+
+ break;
+ case RTM_NEWROUTE:
+ case RTM_DELROUTE:
+ r = socket_broadcast_group_unref(rtnl, RTNLGRP_IPV4_ROUTE);
+ if (r < 0)
+ return r;
+
+ r = socket_broadcast_group_unref(rtnl, RTNLGRP_IPV6_ROUTE);
+ if (r < 0)
+ return r;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
return 1;
}