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net/tcp: Avoid starting TCP sequence number 0

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This commit is contained in:
Alan Carvalho de Assis 2022-11-02 13:40:08 -03:00 committed by Xiang Xiao
parent ab15887a0b
commit 8286a558c8
2 changed files with 47 additions and 0 deletions
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10
net/tcp/tcp_conn.c
View File

@ -1039,6 +1039,10 @@ FAR struct tcp_conn_s *tcp_alloc_accept(FAR struct net_driver_s *dev,
conn->tcpstateflags = TCP_SYN_RCVD; conn->tcpstateflags = TCP_SYN_RCVD;
tcp_initsequence(conn->sndseq); tcp_initsequence(conn->sndseq);
#if !defined(CONFIG_NET_TCP_WRITE_BUFFERS)
conn->rexmit_seq = tcp_getsequence(conn->sndseq);
#endif
conn->tx_unacked = 1; conn->tx_unacked = 1;
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS #ifdef CONFIG_NET_TCP_WRITE_BUFFERS
conn->expired = 0; conn->expired = 0;
@ -1313,6 +1317,12 @@ int tcp_connect(FAR struct tcp_conn_s *conn, FAR const struct sockaddr *addr)
conn->tcpstateflags = TCP_SYN_SENT; conn->tcpstateflags = TCP_SYN_SENT;
tcp_initsequence(conn->sndseq); tcp_initsequence(conn->sndseq);
/* Save initial sndseq to rexmit_seq, otherwise it will be zero */
#if !defined(CONFIG_NET_TCP_WRITE_BUFFERS)
conn->rexmit_seq = tcp_getsequence(conn->sndseq);
#endif
conn->tx_unacked = 1; /* TCP length of the SYN is one. */ conn->tx_unacked = 1; /* TCP length of the SYN is one. */
conn->nrtx = 0; conn->nrtx = 0;
conn->timeout = true; /* Send the SYN immediately. */ conn->timeout = true; /* Send the SYN immediately. */

37
net/tcp/tcp_seqno.c
View File

@ -45,7 +45,9 @@
#include <stdint.h> #include <stdint.h>
#include <debug.h> #include <debug.h>
#include <sys/random.h>
#include <nuttx/clock.h>
#include <nuttx/net/netconfig.h> #include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h> #include <nuttx/net/netdev.h>
@ -142,6 +144,41 @@ uint32_t tcp_addsequence(FAR uint8_t *seqno, uint16_t len)
void tcp_initsequence(FAR uint8_t *seqno) void tcp_initsequence(FAR uint8_t *seqno)
{ {
int ret;
/* If g_tcpsequence is already initialized, just copy it */
if (g_tcpsequence == 0)
{
/* Get a random TCP sequence number */
ret = getrandom(&g_tcpsequence, sizeof(uint32_t), 0);
if (ret < 0)
{
ret = getrandom(&g_tcpsequence, sizeof(uint32_t), GRND_RANDOM);
}
/* If getrandom() failed use sys ticks, use about half of allowed
* values
*/
if (ret != sizeof(uint32_t))
{
g_tcpsequence = clock_systime_ticks() % 2000000000;
}
else
{
g_tcpsequence = g_tcpsequence % 2000000000;
}
/* If the random value is "small" increase it */
if (g_tcpsequence < 1000000000)
{
g_tcpsequence += 1000000000;
}
}
tcp_setsequence(seqno, g_tcpsequence); tcp_setsequence(seqno, g_tcpsequence);
} }