From 9d565427647a874b7eda64ef0cb41ea74a96659b Mon Sep 17 00:00:00 2001 From: Susant Sahani Date: Tue, 2 Aug 2016 23:18:23 +0530 Subject: socket: add support to control no. of connections from one source (#3607) Introduce MaxConnectionsPerSource= that is number of concurrent connections allowed per IP. RFE: 1939 --- man/systemd.socket.xml | 8 ++ src/core/dbus-socket.c | 1 + src/core/load-fragment-gperf.gperf.m4 | 1 + src/core/service.c | 1 + src/core/service.h | 1 + src/core/socket.c | 185 ++++++++++++++++++++++++++++++++++ src/core/socket.h | 16 +++ 7 files changed, 213 insertions(+) diff --git a/man/systemd.socket.xml b/man/systemd.socket.xml index 5bf54d8ef3..26e5d3ce7b 100644 --- a/man/systemd.socket.xml +++ b/man/systemd.socket.xml @@ -443,6 +443,14 @@ + MaxConnectionsPerSource= + The maximum number of connections for a service per source IP address. + This is is very similar to the MaxConnections= directive + above. Disabled by default. + + + + KeepAlive= Takes a boolean argument. If true, the TCP/IP stack will send a keep alive message after 2h (depending on diff --git a/src/core/dbus-socket.c b/src/core/dbus-socket.c index 961340608d..9a071a1355 100644 --- a/src/core/dbus-socket.c +++ b/src/core/dbus-socket.c @@ -137,6 +137,7 @@ const sd_bus_vtable bus_socket_vtable[] = { SD_BUS_PROPERTY("Symlinks", "as", NULL, offsetof(Socket, symlinks), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_PROPERTY("Mark", "i", bus_property_get_int, offsetof(Socket, mark), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_PROPERTY("MaxConnections", "u", bus_property_get_unsigned, offsetof(Socket, max_connections), SD_BUS_VTABLE_PROPERTY_CONST), + SD_BUS_PROPERTY("MaxConnectionsPerSource", "u", bus_property_get_unsigned, offsetof(Socket, max_connections_per_source), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_PROPERTY("MessageQueueMaxMessages", "x", bus_property_get_long, offsetof(Socket, mq_maxmsg), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_PROPERTY("MessageQueueMessageSize", "x", bus_property_get_long, offsetof(Socket, mq_msgsize), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_PROPERTY("ReusePort", "b", bus_property_get_bool, offsetof(Socket, reuse_port), SD_BUS_VTABLE_PROPERTY_CONST), diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4 index c9cdbe8ba7..396f847213 100644 --- a/src/core/load-fragment-gperf.gperf.m4 +++ b/src/core/load-fragment-gperf.gperf.m4 @@ -293,6 +293,7 @@ Socket.DirectoryMode, config_parse_mode, 0, Socket.Accept, config_parse_bool, 0, offsetof(Socket, accept) Socket.Writable, config_parse_bool, 0, offsetof(Socket, writable) Socket.MaxConnections, config_parse_unsigned, 0, offsetof(Socket, max_connections) +Socket.MaxConnectionsPerSource, config_parse_unsigned, 0, offsetof(Socket, max_connections_per_source) Socket.KeepAlive, config_parse_bool, 0, offsetof(Socket, keep_alive) Socket.KeepAliveTimeSec, config_parse_sec, 0, offsetof(Socket, keep_alive_time) Socket.KeepAliveIntervalSec, config_parse_sec, 0, offsetof(Socket, keep_alive_interval) diff --git a/src/core/service.c b/src/core/service.c index 4d59d78ecb..eb125cb999 100644 --- a/src/core/service.c +++ b/src/core/service.c @@ -342,6 +342,7 @@ static void service_done(Unit *u) { s->bus_name_owner = mfree(s->bus_name_owner); service_close_socket_fd(s); + s->peer = socket_peer_unref(s->peer); unit_ref_unset(&s->accept_socket); diff --git a/src/core/service.h b/src/core/service.h index 8e56e1acb9..888007cc0b 100644 --- a/src/core/service.h +++ b/src/core/service.h @@ -152,6 +152,7 @@ struct Service { pid_t main_pid, control_pid; int socket_fd; + SocketPeer *peer; bool socket_fd_selinux_context_net; bool permissions_start_only; diff --git a/src/core/socket.c b/src/core/socket.c index 1ce41a1f07..ff55885fb3 100644 --- a/src/core/socket.c +++ b/src/core/socket.c @@ -57,6 +57,7 @@ #include "unit-printf.h" #include "unit.h" #include "user-util.h" +#include "in-addr-util.h" static const UnitActiveState state_translation_table[_SOCKET_STATE_MAX] = { [SOCKET_DEAD] = UNIT_INACTIVE, @@ -77,6 +78,9 @@ static const UnitActiveState state_translation_table[_SOCKET_STATE_MAX] = { static int socket_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata); static int socket_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata); +SocketPeer *socket_peer_new(void); +int socket_find_peer(Socket *s, int fd, SocketPeer **p); + static void socket_init(Unit *u) { Socket *s = SOCKET(u); @@ -141,11 +145,17 @@ void socket_free_ports(Socket *s) { static void socket_done(Unit *u) { Socket *s = SOCKET(u); + SocketPeer *p; assert(s); socket_free_ports(s); + while ((p = hashmap_steal_first(s->peers_by_address))) + p->socket = NULL; + + s->peers_by_address = hashmap_free(s->peers_by_address); + s->exec_runtime = exec_runtime_unref(s->exec_runtime); exec_command_free_array(s->exec_command, _SOCKET_EXEC_COMMAND_MAX); s->control_command = NULL; @@ -468,6 +478,40 @@ static int socket_verify(Socket *s) { return 0; } +static void peer_address_hash_func(const void *p, struct siphash *state) { + const SocketPeer *s = p; + + assert(s); + + if (s->peer.sa.sa_family == AF_INET) + siphash24_compress(&s->peer.in.sin_addr, sizeof(s->peer.in.sin_addr), state); + else if (s->peer.sa.sa_family == AF_INET6) + siphash24_compress(&s->peer.in6.sin6_addr, sizeof(s->peer.in6.sin6_addr), state); +} + +static int peer_address_compare_func(const void *a, const void *b) { + const SocketPeer *x = a, *y = b; + + if (x->peer.sa.sa_family < y->peer.sa.sa_family) + return -1; + if (x->peer.sa.sa_family > y->peer.sa.sa_family) + return 1; + + switch(x->peer.sa.sa_family) { + case AF_INET: + return memcmp(&x->peer.in.sin_addr, &y->peer.in.sin_addr, sizeof(x->peer.in.sin_addr)); + case AF_INET6: + return memcmp(&x->peer.in6.sin6_addr, &y->peer.in6.sin6_addr, sizeof(x->peer.in6.sin6_addr)); + } + + return -1; +} + +const struct hash_ops peer_address_hash_ops = { + .hash = peer_address_hash_func, + .compare = peer_address_compare_func +}; + static int socket_load(Unit *u) { Socket *s = SOCKET(u); int r; @@ -475,6 +519,10 @@ static int socket_load(Unit *u) { assert(u); assert(u->load_state == UNIT_STUB); + r = hashmap_ensure_allocated(&s->peers_by_address, &peer_address_hash_ops); + if (r < 0) + return r; + r = unit_load_fragment_and_dropin(u); if (r < 0) return r; @@ -2050,6 +2098,7 @@ static void socket_enter_running(Socket *s, int cfd) { socket_set_state(s, SOCKET_RUNNING); } else { _cleanup_free_ char *prefix = NULL, *instance = NULL, *name = NULL; + _cleanup_(socket_peer_unrefp) SocketPeer *p = NULL; Service *service; if (s->n_connections >= s->max_connections) { @@ -2058,6 +2107,21 @@ static void socket_enter_running(Socket *s, int cfd) { return; } + if (s->max_connections_per_source > 0) { + r = socket_find_peer(s, cfd, &p); + if (r < 0) { + safe_close(cfd); + return; + } + + if (p->n_ref > s->max_connections_per_source) { + log_unit_warning(UNIT(s), "Too many incoming connections (%u) from source, refusing connection attempt.", p->n_ref); + safe_close(cfd); + p = NULL; + return; + } + } + r = socket_instantiate_service(s); if (r < 0) goto fail; @@ -2099,6 +2163,11 @@ static void socket_enter_running(Socket *s, int cfd) { cfd = -1; /* We passed ownership of the fd to the service now. Forget it here. */ s->n_connections++; + if (s->max_connections_per_source > 0) { + service->peer = socket_peer_ref(p); + p = NULL; + } + r = manager_add_job(UNIT(s)->manager, JOB_START, UNIT(service), JOB_REPLACE, &error, NULL); if (r < 0) { /* We failed to activate the new service, but it still exists. Let's make sure the service @@ -2244,7 +2313,9 @@ static int socket_stop(Unit *u) { static int socket_serialize(Unit *u, FILE *f, FDSet *fds) { Socket *s = SOCKET(u); + SocketPeer *k; SocketPort *p; + Iterator i; int r; assert(u); @@ -2295,6 +2366,16 @@ static int socket_serialize(Unit *u, FILE *f, FDSet *fds) { } } + HASHMAP_FOREACH(k, s->peers_by_address, i) { + _cleanup_free_ char *t = NULL; + + r = sockaddr_pretty(&k->peer.sa, FAMILY_ADDRESS_SIZE(k->peer.sa.sa_family), true, true, &t); + if (r < 0) + return r; + + unit_serialize_item_format(u, f, "peer", "%u %s", k->n_ref, t); + } + return 0; } @@ -2458,6 +2539,33 @@ static int socket_deserialize_item(Unit *u, const char *key, const char *value, } } + } else if (streq(key, "peer")) { + _cleanup_(socket_peer_unrefp) SocketPeer *p; + int n_ref, skip = 0; + SocketAddress a; + int r; + + if (sscanf(value, "%u %n", &n_ref, &skip) < 1 || n_ref < 1) + log_unit_debug(u, "Failed to parse socket peer value: %s", value); + else { + r = socket_address_parse(&a, value+skip); + if (r < 0) + return r; + + p = socket_peer_new(); + if (!p) + return log_oom(); + + p->n_ref = n_ref; + memcpy(&p->peer, &a.sockaddr, sizeof(a.sockaddr)); + p->socket = s; + + r = hashmap_put(s->peers_by_address, p, p); + if (r < 0) + return r; + + p = NULL; + } } else log_unit_debug(UNIT(s), "Unknown serialization key: %s", key); @@ -2554,6 +2662,83 @@ _pure_ static bool socket_check_gc(Unit *u) { return s->n_connections > 0; } +SocketPeer *socket_peer_new(void) { + SocketPeer *p; + + p = new0(SocketPeer, 1); + if (!p) + return NULL; + + p->n_ref = 1; + + return p; +} + +SocketPeer *socket_peer_ref(SocketPeer *p) { + if (!p) + return NULL; + + assert(p->n_ref > 0); + p->n_ref++; + + return p; +} + +SocketPeer *socket_peer_unref(SocketPeer *p) { + if (!p) + return NULL; + + assert(p->n_ref > 0); + + p->n_ref--; + + if (p->n_ref > 0) + return NULL; + + if (p->socket) + (void) hashmap_remove(p->socket->peers_by_address, p); + + free(p); + + return NULL; +} + +int socket_find_peer(Socket *s, int fd, SocketPeer **p) { + _cleanup_free_ SocketPeer *remote = NULL; + SocketPeer sa, *i; + socklen_t salen = sizeof(sa.peer); + int r; + + assert(fd >= 0); + assert(s); + + r = getpeername(fd, &sa.peer.sa, &salen); + if (r < 0) + return log_error_errno(errno, "getpeername failed: %m"); + + i = hashmap_get(s->peers_by_address, &sa); + if (i) { + *p = i; + return 1; + } + + remote = socket_peer_new(); + if (!remote) + return log_oom(); + + memcpy(&remote->peer, &sa.peer, sizeof(union sockaddr_union)); + remote->socket = s; + + r = hashmap_put(s->peers_by_address, remote, remote); + if (r < 0) + return r; + + *p = remote; + remote = NULL; + + return 0; +} + static int socket_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) { SocketPort *p = userdata; int cfd = -1; diff --git a/src/core/socket.h b/src/core/socket.h index 6c32d67bef..2fe38ef2aa 100644 --- a/src/core/socket.h +++ b/src/core/socket.h @@ -20,6 +20,7 @@ ***/ typedef struct Socket Socket; +typedef struct SocketPeer SocketPeer; #include "mount.h" #include "service.h" @@ -79,9 +80,12 @@ struct Socket { LIST_HEAD(SocketPort, ports); + Hashmap *peers_by_address; + unsigned n_accepted; unsigned n_connections; unsigned max_connections; + unsigned max_connections_per_source; unsigned backlog; unsigned keep_alive_cnt; @@ -164,6 +168,18 @@ struct Socket { RateLimit trigger_limit; }; +struct SocketPeer { + unsigned n_ref; + + Socket *socket; + union sockaddr_union peer; +}; + +SocketPeer *socket_peer_ref(SocketPeer *p); +SocketPeer *socket_peer_unref(SocketPeer *p); + +DEFINE_TRIVIAL_CLEANUP_FUNC(SocketPeer*, socket_peer_unref); + /* Called from the service code when collecting fds */ int socket_collect_fds(Socket *s, int **fds); -- cgit v1.2.3-54-g00ecf