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-rw-r--r--accel-pppd/ctrl/l2tp/l2tp.c392
1 files changed, 262 insertions, 130 deletions
diff --git a/accel-pppd/ctrl/l2tp/l2tp.c b/accel-pppd/ctrl/l2tp/l2tp.c
index 8c06cd43..a61694db 100644
--- a/accel-pppd/ctrl/l2tp/l2tp.c
+++ b/accel-pppd/ctrl/l2tp/l2tp.c
@@ -67,6 +67,7 @@
*/
#define RECV_WINDOW_SIZE_MAX 32768
+#define DEFAULT_RECV_WINDOW 16
#define DEFAULT_PPP_MAX_MTU 1420
int conf_verbose = 0;
@@ -160,6 +161,9 @@ struct l2tp_conn_t
struct list_head send_queue;
struct list_head rtms_queue;
unsigned int send_queue_len;
+ struct l2tp_packet_t **recv_queue;
+ uint16_t recv_queue_sz;
+ uint16_t recv_queue_offt;
uint16_t peer_rcv_wnd_sz;
unsigned int ref_count;
@@ -450,6 +454,21 @@ static int l2tp_tunnel_checkchallresp(uint8_t msgident,
return 0;
}
+static void l2tp_tunnel_clear_recvqueue(struct l2tp_conn_t *conn)
+{
+ struct l2tp_packet_t *pack;
+ uint16_t id;
+
+ for (id = 0; id < conn->recv_queue_sz; ++id) {
+ pack = conn->recv_queue[id];
+ if (pack) {
+ l2tp_packet_free(pack);
+ conn->recv_queue[id] = NULL;
+ }
+ }
+ conn->recv_queue_offt = 0;
+}
+
static void l2tp_tunnel_clear_sendqueue(struct l2tp_conn_t *conn)
{
struct l2tp_packet_t *pack;
@@ -896,6 +915,8 @@ static void __tunnel_destroy(struct l2tp_conn_t *conn)
_free(conn->challenge);
if (conn->secret)
_free(conn->secret);
+ if (conn->recv_queue)
+ _free(conn->recv_queue);
log_tunnel(log_info2, conn, "tunnel destroyed\n");
@@ -1115,6 +1136,9 @@ static void l2tp_tunnel_free(struct l2tp_conn_t *conn)
}
l2tp_tunnel_clear_sendqueue(conn);
+ if (conn->recv_queue)
+ l2tp_tunnel_clear_recvqueue(conn);
+
if (conn->sessions)
l2tp_tunnel_free_sessions(conn);
@@ -1600,13 +1624,26 @@ static struct l2tp_conn_t *l2tp_tunnel_alloc(const struct sockaddr_in *peer,
goto err_conn_fd;
}
+ conn->recv_queue_sz = DEFAULT_RECV_WINDOW;
+ conn->recv_queue = _malloc(conn->recv_queue_sz *
+ sizeof(*conn->recv_queue));
+ if (conn->recv_queue == NULL) {
+ log_error("l2tp: impossible to allocate new tunnel:"
+ " allocating reception queue (%zu bytes) failed\n",
+ conn->recv_queue_sz * sizeof(*conn->recv_queue));
+ goto err_conn_fd;
+ }
+ memset(conn->recv_queue, 0,
+ conn->recv_queue_sz * sizeof(*conn->recv_queue));
+ conn->recv_queue_offt = 0;
+
for (count = UINT16_MAX; count > 0; --count) {
rdlen = read(urandom_fd, &conn->tid, sizeof(conn->tid));
if (rdlen != sizeof(conn->tid)) {
log_error("l2tp: impossible to allocate new tunnel:"
" reading from urandom failed: %s\n",
(rdlen < 0) ? strerror(errno) : "short read");
- goto err_conn_fd;
+ goto err_conn_fd_queue;
}
if (conn->tid == 0)
@@ -1626,7 +1663,7 @@ static struct l2tp_conn_t *l2tp_tunnel_alloc(const struct sockaddr_in *peer,
if (count == 0) {
log_error("l2tp: impossible to allocate new tunnel:"
" could not find any unused tunnel ID\n");
- goto err_conn_fd;
+ goto err_conn_fd_queue;
}
conn->state = STATE_INIT;
@@ -1654,6 +1691,8 @@ static struct l2tp_conn_t *l2tp_tunnel_alloc(const struct sockaddr_in *peer,
return conn;
+err_conn_fd_queue:
+ _free(conn->recv_queue);
err_conn_fd:
close(conn->hnd.fd);
err_conn:
@@ -1962,26 +2001,6 @@ err:
return -1;
}
-static int l2tp_retransmit(struct l2tp_conn_t *conn)
-{
- struct l2tp_packet_t *pack;
-
- pack = list_first_entry(&conn->rtms_queue, typeof(*pack), entry);
- log_tunnel(log_info2, conn, "retransmitting packet %hu\n",
- ntohs(pack->hdr.Ns));
- if (conf_verbose) {
- log_tunnel(log_info2, conn, "retransmit (duplicate) ");
- l2tp_packet_print(pack, log_info2);
- }
- if (__l2tp_tunnel_send(conn, pack) < 0) {
- log_tunnel(log_error, conn,
- "packet retransmission failure\n");
- return -1;
- }
-
- return 0;
-}
-
static void l2tp_rtimeout(struct triton_timer_t *t)
{
struct l2tp_conn_t *conn = container_of(t, typeof(*conn), rtimeout_timer);
@@ -2130,6 +2149,12 @@ static void l2tp_send_SCCRQ(void *peer_addr)
" adding data to packet failed\n");
goto pack_err;
}
+ if (l2tp_packet_add_int16(pack, Recv_Window_Size, conn->recv_queue_sz,
+ 1) < 0) {
+ log_tunnel(log_error, conn, "impossible to send SCCRQ:"
+ " adding data to packet failed\n");
+ goto pack_err;
+ }
if (u_randbuf(&chall_len, sizeof(chall_len), &err) < 0) {
if (err)
@@ -2212,6 +2237,12 @@ static void l2tp_send_SCCRP(struct l2tp_conn_t *conn)
" adding data to packet failed\n");
goto out_err;
}
+ if (l2tp_packet_add_int16(pack, Recv_Window_Size, conn->recv_queue_sz,
+ 1) < 0) {
+ log_tunnel(log_error, conn, "impossible to send SCCRP:"
+ " adding data to packet failed\n");
+ goto out_err;
+ }
if (l2tp_tunnel_genchallresp(Message_Type_Start_Ctrl_Conn_Reply,
conn, pack) < 0) {
@@ -3900,14 +3931,191 @@ static void l2tp_tunnel_recv(struct l2tp_conn_t *conn,
}
}
+static int l2tp_tunnel_store_msg(struct l2tp_conn_t *conn,
+ struct l2tp_packet_t *pack,
+ int *need_ack)
+{
+ uint16_t pack_Ns = ntohs(pack->hdr.Ns);
+ uint16_t pack_Nr = ntohs(pack->hdr.Nr);
+ uint16_t indx;
+
+ /* Drop packets which acknowledge more packets than have actually
+ * been sent.
+ */
+ if (nsnr_cmp(conn->Ns, pack_Nr) < 0) {
+ log_tunnel(log_warn, conn,
+ "discarding message acknowledging unsent packets"
+ " (packet Ns/Nr: %hu/%hu, tunnel Ns/Nr: %hu/%hu)\n",
+ pack_Ns, pack_Nr, conn->Ns, conn->Nr);
+
+ return -1;
+ }
+
+ /* Update peer Nr only when new packets are acknowledged */
+ if (nsnr_cmp(pack_Nr, conn->peer_Nr) > 0)
+ conn->peer_Nr = pack_Nr;
+
+ if (l2tp_packet_is_ZLB(pack)) {
+ log_tunnel(log_debug, conn, "handling ZLB\n");
+ if (conf_verbose) {
+ log_tunnel(log_debug, conn, "recv ");
+ l2tp_packet_print(pack, log_debug);
+ }
+
+ return -1;
+ }
+
+ /* From now on, acknowledgement has to be sent in any case:
+ * -If the received packet is a duplicated message, the ack will
+ * let the peer know we received its message (in case our
+ * previous ack was lost).
+ *
+ * -If the received packet is an out of order message (whether or not
+ * it fits in our reception window), the ack will explicitly tell the
+ * peer which message number we're missing.
+ */
+ *need_ack = 1;
+
+ /* Drop duplicate messages */
+ if (nsnr_cmp(pack_Ns, conn->Nr) < 0) {
+ log_tunnel(log_info2, conn, "handling duplicate message"
+ " (packet Ns/Nr: %hu/%hu, tunnel Ns/Nr: %hu/%hu)\n",
+ pack_Ns, pack_Nr, conn->Ns, conn->Nr);
+
+ return -1;
+ }
+
+ /* Drop out of order messages which don't fit in our reception queue.
+ * This means that the peer doesn't respect our receive window, so use
+ * log_warn.
+ */
+ indx = pack_Ns - conn->Nr;
+ if (indx >= conn->recv_queue_sz) {
+ log_tunnel(log_warn, conn, "discarding out of order message"
+ " (packet Ns/Nr: %hu/%hu, tunnel Ns/Nr: %hu/%hu,"
+ " tunnel reception window size: %hu bytes)\n",
+ pack_Ns, pack_Nr, conn->Ns, conn->Nr,
+ conn->recv_queue_sz);
+
+ return -1;
+ }
+
+ /* Drop duplicate out of order messages */
+ indx = (indx + conn->recv_queue_offt) % conn->recv_queue_sz;
+ if (conn->recv_queue[indx]) {
+ log_tunnel(log_info2, conn,
+ "discarding duplicate out of order message"
+ " (packet Ns/Nr: %hu/%hu, tunnel Ns/Nr: %hu/%hu)\n",
+ pack_Ns, pack_Nr, conn->Ns, conn->Nr);
+
+ return -1;
+ }
+
+ conn->recv_queue[indx] = pack;
+
+ return 0;
+}
+
+static int l2tp_tunnel_reply(struct l2tp_conn_t *conn, int need_ack)
+{
+ const struct l2tp_attr_t *msg_attr;
+ struct l2tp_packet_t *pack;
+ struct l2tp_sess_t *sess;
+ uint16_t msg_sid;
+ uint16_t msg_type;
+ uint16_t id = conn->recv_queue_offt;
+ unsigned int pkt_count = 0;
+ int res;
+
+ /* Loop over reception queue, break as as soon as there is no more
+ * message to process or if tunnel gets closed.
+ */
+ do {
+ if (conn->recv_queue[id] == NULL || conn->state == STATE_CLOSE)
+ break;
+
+ pack = conn->recv_queue[id];
+ conn->recv_queue[id] = NULL;
+ ++conn->Nr;
+ ++pkt_count;
+ id = (id + 1) % conn->recv_queue_sz;
+
+ /* We may receive packets even while disconnecting (e.g.
+ * packets sent by peer before we disconnect, but received
+ * later on).
+ * We don't have to process these messages, but we still
+ * dequeue them all to send proper acknowledgement (to avoid
+ * useless retransmissions from peer). Log with log_info2 since
+ * there's nothing wrong with receiving messages at this stage.
+ */
+ if (conn->state == STATE_FIN) {
+ log_tunnel(log_info2, conn,
+ "discarding message received while disconnecting\n");
+ l2tp_packet_free(pack);
+ continue;
+ }
+
+ /* ZLB aren't stored in the reception queue, so we're sure that
+ * pack->attrs isn't an empty list.
+ */
+ msg_attr = list_first_entry(&pack->attrs, typeof(*msg_attr),
+ entry);
+ if (msg_attr->attr->id != Message_Type) {
+ log_tunnel(log_warn, conn,
+ "discarding message with invalid first attribute type %hu\n",
+ msg_attr->attr->id);
+ l2tp_packet_free(pack);
+ continue;
+ }
+ msg_type = msg_attr->val.uint16;
+
+ if (conf_verbose) {
+ if (msg_type == Message_Type_Hello) {
+ log_tunnel(log_debug, conn, "recv ");
+ l2tp_packet_print(pack, log_debug);
+ } else {
+ log_tunnel(log_info2, conn, "recv ");
+ l2tp_packet_print(pack, log_info2);
+ }
+ }
+
+ msg_sid = ntohs(pack->hdr.sid);
+ if (msg_sid) {
+ sess = l2tp_tunnel_get_session(conn, msg_sid);
+ if (sess == NULL) {
+ log_tunnel(log_warn, conn,
+ "discarding message with invalid Session ID %hu\n",
+ msg_sid);
+ l2tp_packet_free(pack);
+ continue;
+ }
+ l2tp_session_recv(sess, pack, msg_type, msg_attr->M);
+ } else {
+ l2tp_tunnel_recv(conn, pack, msg_type, msg_attr->M);
+ }
+
+ l2tp_packet_free(pack);
+ } while (id != conn->recv_queue_offt);
+
+ conn->recv_queue_offt = (conn->recv_queue_offt + pkt_count) % conn->recv_queue_sz;
+
+ log_tunnel(log_debug, conn,
+ "%u message%s processed from reception queue\n",
+ pkt_count, pkt_count > 1 ? "s" : "");
+
+ res = l2tp_tunnel_push_sendqueue(conn);
+ if (res == 0 && need_ack)
+ res = l2tp_send_ZLB(conn);
+
+ return res;
+}
+
static int l2tp_conn_read(struct triton_md_handler_t *h)
{
struct l2tp_conn_t *conn = container_of(h, typeof(*conn), hnd);
- struct l2tp_sess_t *sess = NULL;
struct l2tp_packet_t *pack;
- const struct l2tp_attr_t *msg_type;
- uint16_t m_type;
- uint16_t m_sid;
+ unsigned int pkt_count = 0;
+ int need_ack = 0;
int res;
/* Hold the tunnel. This allows any function we call to free the
@@ -3944,7 +4152,8 @@ static int l2tp_conn_read(struct triton_md_handler_t *h)
log_tunnel(log_error, conn,
"peer port update failed,"
" disconnecting tunnel\n");
- goto drop;
+ l2tp_packet_free(pack);
+ goto err_tunfree;
}
conn->port_set = 1;
}
@@ -3957,115 +4166,40 @@ static int l2tp_conn_read(struct triton_md_handler_t *h)
continue;
}
- if (nsnr_cmp(ntohs(pack->hdr.Nr), conn->peer_Nr) > 0)
- conn->peer_Nr = ntohs(pack->hdr.Nr);
-
- /* Drop acknowledged packets from retransmission queue */
- if (l2tp_tunnel_clean_rtmsqueue(conn) < 0) {
- log_tunnel(log_error, conn,
- "impossible to handle incoming message:"
- " cleaning retransmission queue failed\n");
- goto drop;
- }
-
- res = nsnr_cmp(ntohs(pack->hdr.Ns), conn->Nr);
- if (res < 0) {
- /* Duplicate message */
- log_tunnel(log_info2, conn,
- "handling duplicate message (packet Ns/Nr:"
- " %hu/%hu, tunnel Ns/Nr: %hu/%hu)\n",
- ntohs(pack->hdr.Ns), ntohs(pack->hdr.Nr),
- conn->Ns, conn->Nr);
- if (!list_empty(&conn->rtms_queue))
- res = l2tp_retransmit(conn);
- else
- res = l2tp_send_ZLB(conn);
- if (res < 0)
- log_tunnel(log_warn, conn,
- "replying to duplicate message"
- " failed, continuing anyway\n");
- l2tp_packet_free(pack);
- continue;
- } else if (res > 0) {
- /* Out of order message */
- log_tunnel(log_info2, conn,
- "discarding reordered message (packet Ns/Nr:"
- " %hu/%hu, tunnel Ns/Nr: %hu/%hu)\n",
- ntohs(pack->hdr.Ns), ntohs(pack->hdr.Nr),
- conn->Ns, conn->Nr);
+ if (l2tp_tunnel_store_msg(conn, pack, &need_ack) < 0) {
l2tp_packet_free(pack);
continue;
- } else {
- if (!list_empty(&pack->attrs))
- conn->Nr++;
-
- if (conn->state == STATE_FIN)
- goto drop;
}
- if (list_empty(&pack->attrs)) {
- log_tunnel(log_debug, conn, "handling ZLB\n");
- if (conf_verbose) {
- log_tunnel(log_debug, conn, "recv ");
- l2tp_packet_print(pack, log_debug);
- }
- l2tp_packet_free(pack);
- continue;
- }
-
- msg_type = list_entry(pack->attrs.next, typeof(*msg_type), entry);
-
- if (msg_type->attr->id != Message_Type) {
- log_tunnel(log_warn, conn,
- "discarding message with invalid first"
- " attribute type %i\n", msg_type->attr->id);
- l2tp_packet_free(pack);
- continue;
- }
- m_type = msg_type->val.uint16;
+ ++pkt_count;
+ }
- if (conf_verbose) {
- if (m_type == Message_Type_Hello) {
- log_tunnel(log_debug, conn, "recv ");
- l2tp_packet_print(pack, log_debug);
- } else {
- log_tunnel(log_info2, conn, "recv ");
- l2tp_packet_print(pack, log_info2);
- }
- }
+ log_tunnel(log_debug, conn, "%u message%s added to reception queue\n",
+ pkt_count, pkt_count > 1 ? "s" : "");
- m_sid = ntohs(pack->hdr.sid);
- if (m_sid) {
- sess = l2tp_tunnel_get_session(conn, m_sid);
- if (sess == NULL) {
- log_tunnel(log_warn, conn,
- "discarding message with invalid Session ID %hu\n",
- m_sid);
- l2tp_packet_free(pack);
- continue;
- }
- l2tp_session_recv(sess, pack, m_type, msg_type->M);
- } else {
- l2tp_tunnel_recv(conn, pack, m_type, msg_type->M);
- }
+ /* Drop acknowledged packets from retransmission queue */
+ if (l2tp_tunnel_clean_rtmsqueue(conn) < 0) {
+ log_tunnel(log_error, conn,
+ "impossible to handle incoming message:"
+ " cleaning retransmission queue failed,"
+ " deleting tunnel\n");
+ goto err_tunfree;
+ }
- res = l2tp_tunnel_push_sendqueue(conn);
- if (res < 0) {
- log_tunnel(log_error, conn,
- "impossible to reply to incoming message:"
- " transmitting messages from send queue failed,"
- " deleting tunnel\n");
- goto drop;
- } else if (res == 0) {
- if (l2tp_send_ZLB(conn) < 0) {
- log_tunnel(log_error, conn,
- "impossible to acknowledge messages from peer:"
- " sending ZBL failed\n");
- goto drop;
- }
- }
+ if (l2tp_tunnel_reply(conn, need_ack) < 0) {
+ log_tunnel(log_error, conn,
+ "impossible to reply to incoming messages:"
+ " message transmission failed,"
+ " deleting tunnel\n");
+ goto err_tunfree;
+ }
- l2tp_packet_free(pack);
+ if (conn->state == STATE_FIN && list_empty(&conn->send_queue) &&
+ list_empty(&conn->rtms_queue)) {
+ log_tunnel(log_info2, conn,
+ "tunnel disconnection acknowledged by peer,"
+ " deleting tunnel\n");
+ goto err_tunfree;
}
/* Use conn->state to detect tunnel deletion */
@@ -4076,8 +4210,6 @@ static int l2tp_conn_read(struct triton_md_handler_t *h)
return 0;
-drop:
- l2tp_packet_free(pack);
err_tunfree:
l2tp_tunnel_free(conn);
err:
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-20 21:41:36 +0000