net: tcp: Add retry handling (01f5fbda) · Commits · Wenxi XU / zephyr

net/yaip/tcp.c

+68 −1

Original line number	Diff line number	Diff line
		@@ -52,6 +52,8 @@
		#define NET_MAX_TCP_CONTEXT CONFIG_NET_MAX_CONTEXTS
		static struct net_tcp tcp_context[NET_MAX_TCP_CONTEXT];

		#define INIT_RETRY_MS 200

		static struct k_sem tcp_lock;

		struct tcp_segment {
		@@ -110,6 +112,24 @@ static inline uint32_t init_isn(void)
		return sys_rand32_get();
		}

		static void tcp_retry_expired(struct k_timer *timer)
		{
		struct net_tcp *tcp = CONTAINER_OF(timer, struct net_tcp, retry_timer);
		struct net_buf *buf;

		/* Double the retry period for exponential backoff and resent
		* the first (only the first!) unack'd packet.
		*/
		if (!sys_slist_is_empty(&tcp->sent_list)) {
		tcp->retry_timeout_ms *= 2;
		k_timer_start(&tcp->retry_timer, tcp->retry_timeout_ms, 0);

		buf = CONTAINER_OF(sys_slist_peek_head(&tcp->sent_list),
		struct net_buf, sent_list);
		net_tcp_send_buf(buf);
		}
		}

		struct net_tcp net_tcp_alloc(struct net_context context)
		{
		int i, key;
		@@ -136,6 +156,8 @@ struct net_tcp net_tcp_alloc(struct net_context context)
		tcp_context[i].send_seq = init_isn();
		tcp_context[i].recv_max_ack = tcp_context[i].send_seq + 1u;

		k_timer_init(&tcp_context[i].retry_timer, tcp_retry_expired, NULL);

		return &tcp_context[i];
		}

		@@ -601,9 +623,23 @@ int net_tcp_send_buf(struct net_buf *buf)

		ctx->tcp->sent_ack = ctx->tcp->send_ack;

		net_nbuf_set_buf_sent(buf, true);

		return net_send_data(buf);
		}

		static void restart_timer(struct net_tcp *tcp)
		{
		if (sys_slist_is_empty(&tcp->sent_list)) {
		tcp->flags \|= NET_TCP_RETRYING;
		tcp->retry_timeout_ms = INIT_RETRY_MS;
		k_timer_start(&tcp->retry_timer, INIT_RETRY_MS, 0);
		} else {
		k_timer_stop(&tcp->retry_timer);
		tcp->flags &= ~NET_TCP_RETRYING;
		}
		}

		int tcp_send_data(struct net_context *context)
		{
		struct net_buf *buf;
		@@ -614,8 +650,10 @@ int tcp_send_data(struct net_context *context)
		*/
		SYS_SLIST_FOR_EACH_NODE(&context->tcp->sent_list, node) {
		buf = CONTAINER_OF(node, struct net_buf, sent_list);
		if (!net_nbuf_buf_sent(buf)) {
		net_tcp_send_buf(buf);
		}
		}

		return 0;
		}
		@@ -627,6 +665,7 @@ void net_tcp_ack_received(struct net_context *ctx, uint32_t ack)
		struct net_buf *buf;
		struct net_tcp_hdr *tcphdr;
		uint32_t seq;
		bool valid_ack = false;

		while (!sys_slist_is_empty(list)) {
		head = sys_slist_peek_head(list);
		@@ -639,10 +678,38 @@ void net_tcp_ack_received(struct net_context *ctx, uint32_t ack)
		if (seq_greater(ack, seq)) {
		sys_slist_remove(list, NULL, head);
		net_nbuf_unref(buf);
		valid_ack = true;
		} else {
		break;
		}
		}

		if (valid_ack) {
		/* Restart the timer on a valid inbound ACK. This
		* isn't quite the same behavior as per-packet retry
		* timers, but is close in practice (it starts retries
		* one timer period after the connection "got stuck")
		* and avoids the need to track per-packet timers or
		* sent times.
		*/
		restart_timer(ctx->tcp);

		/* And, if we had been retrying, mark all packets
		* untransmitted and then resend them. The stalled
		* pipe is uncorked again.
		*/
		if (ctx->tcp->flags & NET_TCP_RETRYING) {
		struct net_buf *buf;
		sys_snode_t *node;

		SYS_SLIST_FOR_EACH_NODE(&ctx->tcp->sent_list, node) {
		buf = CONTAINER_OF(node, struct net_buf,
		sent_list);
		net_nbuf_set_buf_sent(buf, false);
		}
		tcp_send_data(ctx);
		}
		}
		}

		void net_tcp_init(void)

net/yaip/tcp.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -48,6 +48,9 @@ extern "C" {
		/** Is the socket shutdown for read/write */
		#define NET_TCP_IS_SHUTDOWN BIT(3)

		/** A retransmitted packet has been sent and not yet ack'd */
		#define NET_TCP_RETRYING BIT(4)

		/*
		* TCP connection states
		*/
		@@ -114,6 +117,12 @@ struct net_tcp {
		/** Active close timer */
		struct k_delayed_work fin_timer;

		/** Retransmit timer */
		struct k_timer retry_timer;

		/** Current retransmit period */
		uint32_t retry_timeout_ms;

		/** List pointer used for TCP retransmit buffering */
		sys_slist_t sent_list;

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