rawapi.txt, api_msg.c, tcp.c, tcp_in.c, tcp.h: changes for task #7675 "Enable to refuse data on a TCP_EVENT_RECV call". Important, behavior changes for the tcp_recv callback (see rawapi.txt).
diff --git a/CHANGELOG b/CHANGELOG
index 4b0ea05..ca190ea 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -19,6 +19,11 @@
++ New features:
+ 2008-01-14 Frédéric Bernon
+ * rawapi.txt, api_msg.c, tcp.c, tcp_in.c, tcp.h: changes for task #7675 "Enable
+ to refuse data on a TCP_EVENT_RECV call". Important, behavior changes for the
+ tcp_recv callback (see rawapi.txt).
+
2008-01-14 Frédéric Bernon, Marc Chaland
* ip.c: Integrate patch #6369" ip_input : checking before realloc".
diff --git a/doc/rawapi.txt b/doc/rawapi.txt
index 93c0e86..8213445 100644
--- a/doc/rawapi.txt
+++ b/doc/rawapi.txt
@@ -188,7 +188,10 @@
Sets the callback function that will be called when new data
arrives. The callback function will be passed a NULL pbuf to
- indicate that the remote host has closed the connection.
+ indicate that the remote host has closed the connection. If
+ there are no errors and the callback function is to return
+ ERR_OK, then it must free the pbuf. Otherwise, it must not
+ free the pbuf so that lwIP core code can store it.
- void tcp_recved(struct tcp_pcb *pcb, u16_t len)
diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index ccb4c0d..3464d07 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -165,7 +165,7 @@
#if LWIP_TCP
/**
* Receive callback function for TCP netconns.
- * Posts the packet to conn->recvmbox or deletes it on memory error.
+ * Posts the packet to conn->recvmbox, but doesn't delete it on errors.
*
* @see tcp.h (struct tcp_pcb.recv) for parameters and return value
*/
@@ -182,7 +182,6 @@
LWIP_ASSERT("recv_tcp: recv for wrong pcb!", conn->pcb.tcp == pcb);
if ((conn == NULL) || (conn->recvmbox == SYS_MBOX_NULL)) {
- pbuf_free(p);
return ERR_VAL;
}
@@ -195,7 +194,9 @@
}
/* Register event with callback */
API_EVENT(conn, NETCONN_EVT_RCVPLUS, len);
- sys_mbox_post(conn->recvmbox, p);
+ if (sys_mbox_trypost(conn->recvmbox, p) != ERR_OK) {
+ return ERR_MEM;
+ }
return ERR_OK;
}
diff --git a/src/core/tcp.c b/src/core/tcp.c
index 24ea5e7..531b26d 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -770,7 +770,8 @@
}
/**
- * Is called every TCP_FAST_INTERVAL (250 ms) and sends delayed ACKs.
+ * Is called every TCP_FAST_INTERVAL (250 ms) and process data previously
+ * "refused" by upper layer (application) and sends delayed ACKs.
*
* Automatically called from tcp_tmr().
*/
@@ -779,8 +780,19 @@
{
struct tcp_pcb *pcb;
- /* send delayed ACKs */
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+ /* If there is data which was previously "refused" by upper layer */
+ if (pcb->refused_data != NULL) {
+ /* Notify again application with data previously received. */
+ err_t err;
+ LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_fasttmr: notify kept packet\n"));
+ TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
+ if (err == ERR_OK) {
+ pcb->refused_data = NULL;
+ }
+ }
+
+ /* send delayed ACKs */
if (pcb->flags & TF_ACK_DELAY) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n"));
tcp_ack_now(pcb);
@@ -1135,15 +1147,20 @@
pcb->state != LISTEN) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
-
- if (pcb->unsent != NULL) {
+
+ if (pcb->refused_data != NULL) {
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->refused_data\n"));
+ pbuf_free(pcb->refused_data);
+ pcb->refused_data = NULL;
+ }
+ if (pcb->unsent != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n"));
}
- if (pcb->unacked != NULL) {
+ if (pcb->unacked != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n"));
}
#if TCP_QUEUE_OOSEQ /* LW */
- if (pcb->ooseq != NULL) {
+ if (pcb->ooseq != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n"));
}
diff --git a/src/core/tcp_in.c b/src/core/tcp_in.c
index 4b7b919..f394312 100644
--- a/src/core/tcp_in.c
+++ b/src/core/tcp_in.c
@@ -272,6 +272,23 @@
recv_data = NULL;
recv_flags = 0;
+ /* If there is data which was previously "refused" by upper layer */
+ if (pcb->refused_data != NULL) {
+ /* Notify again application with data previously received. */
+ LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
+ TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
+ if (err == ERR_OK) {
+ pcb->refused_data = NULL;
+ } else {
+ /* drop incoming packets, because pcb is "full" */
+ LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
+ TCP_STATS_INC(tcp.drop);
+ snmp_inc_tcpinerrs();
+ pbuf_free(p);
+ return;
+ }
+ }
+
tcp_input_pcb = pcb;
err = tcp_process(pcb);
tcp_input_pcb = NULL;
@@ -304,15 +321,23 @@
if(flags & TCP_PSH) {
recv_data->flags |= PBUF_FLAG_PUSH;
}
+
/* Notify application that data has been received. */
TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
+
+ /* If the upper layer can't receive this data, store it */
+ if (err != ERR_OK) {
+ pcb->refused_data = recv_data;
+ LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
+ }
}
-
+
/* If a FIN segment was received, we call the callback
function with a NULL buffer to indicate EOF. */
if (recv_flags & TF_GOT_FIN) {
TCP_EVENT_RECV(pcb, NULL, ERR_OK, err);
}
+
/* If there were no errors, we try to send something out. */
if (err == ERR_OK) {
tcp_output(pcb);
diff --git a/src/include/lwip/tcp.h b/src/include/lwip/tcp.h
index aa949e4..3fb0446 100644
--- a/src/include/lwip/tcp.h
+++ b/src/include/lwip/tcp.h
@@ -339,6 +339,8 @@
struct tcp_seg *ooseq; /* Received out of sequence segments. */
#endif /* TCP_QUEUE_OOSEQ */
+ struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
+
#if LWIP_CALLBACK_API
/* Function to be called when more send buffer space is available.
* @param arg user-supplied argument (tcp_pcb.callback_arg)
@@ -471,6 +473,7 @@
#define TCP_EVENT_RECV(pcb,p,err,ret) \
if((pcb)->recv != NULL) \
{ ret = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err)); } else { \
+ ret = ERR_OK; \
if (p) pbuf_free(p); }
#define TCP_EVENT_CONNECTED(pcb,err,ret) \
if((pcb)->connected != NULL) \
