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net: tcp: Implement Nagle's algorithm

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To improve the performance with small chunks send, implement Nagle's
algorithm. Provide the option TCP_NODELAY to disable the algorithm.

Signed-off-by: Sjors Hettinga <s.a.hettinga@gmail.com>
This commit is contained in:
Sjors Hettinga 2022-06-06 22:00:01 +02:00 • committed by Carles Cufí
commit e097d95c66
4 changed files with 160 additions and 4 deletions
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95
subsys/net/ip/tcp.c
View file

@ -848,6 +848,37 @@ static int ip_header_add(struct tcp *conn, struct net_pkt *pkt)
return -EINVAL;
}
static int set_tcp_nodelay(struct tcp *conn, const void *value, size_t len)
{
int no_delay_int;
if (len != sizeof(int)) {
return -EINVAL;
}
no_delay_int = *(int *)value;
if ((no_delay_int < 0) || (no_delay_int > 1)) {
return -EINVAL;
}
conn->tcp_nodelay = (bool)no_delay_int;
return 0;
}
static int get_tcp_nodelay(struct tcp *conn, void *value, size_t *len)
{
int no_delay_int = (int)conn->tcp_nodelay;
*((int *)value) = no_delay_int;
if (len) {
*len = sizeof(int);
}
return 0;
}
static int net_tcp_set_mss_opt(struct tcp *conn, struct net_pkt *pkt)
{
NET_PKT_DATA_ACCESS_DEFINE(mss_opt_access, struct tcp_mss_option);
@ -1097,6 +1128,19 @@ static int tcp_send_queued_data(struct tcp *conn)
}
while (tcp_unsent_len(conn) > 0) {
/* Implement Nagle's algorithm */
if ((conn->tcp_nodelay == false) && (conn->unacked_len > 0)) {
/* If there is already pending data */
if (tcp_unsent_len(conn) < conn_mss(conn)) {
/* The number of bytes to be transmitted is less than an MSS,
* skip transmission for now.
* Wait for more data to be transmitted or all pending data
* being acknowledged.
*/
break;
}
}
ret = tcp_send_data(conn);
if (ret < 0) {
break;
@ -1301,6 +1345,7 @@ static struct tcp *tcp_conn_alloc(struct net_context *context)
conn->in_connect = false;
conn->state = TCP_LISTEN;
conn->recv_win = tcp_window;
conn->tcp_nodelay = false;
/* Set the recv_win with the rcvbuf configured for the socket. */
if (IS_ENABLED(CONFIG_NET_CONTEXT_RCVBUF) &&
@ -2994,6 +3039,56 @@ uint16_t net_tcp_get_supported_mss(const struct tcp *conn)
return 0;
}
int net_tcp_set_option(struct net_context *context,
enum tcp_conn_option option,
const void *value, size_t len)
{
int ret = 0;
NET_ASSERT(context);
struct tcp *conn = context->tcp;
NET_ASSERT(conn);
k_mutex_lock(&conn->lock, K_FOREVER);
switch (option) {
case TCP_OPT_NODELAY:
ret = set_tcp_nodelay(conn, value, len);
break;
}
k_mutex_unlock(&conn->lock);
return ret;
}
int net_tcp_get_option(struct net_context *context,
enum tcp_conn_option option,
void *value, size_t *len)
{
int ret = 0;
NET_ASSERT(context);
struct tcp *conn = context->tcp;
NET_ASSERT(conn);
k_mutex_lock(&conn->lock, K_FOREVER);
switch (option) {
case TCP_OPT_NODELAY:
ret = get_tcp_nodelay(conn, value, len);
break;
}
k_mutex_unlock(&conn->lock);
return ret;
}
const char *net_tcp_state_str(enum tcp_state state)
{
return tcp_state_to_str(state, false);