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PPP, VJ, fixed TCP retransmission

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We used to modify in place the packet payload during compression but TCP
stack requires that we don't change the packet payload, therefore we now
copy the whole packet before compression.

Signed-off-by: Sylvain Rochet <gradator@gradator.net>
This commit is contained in:
Sylvain Rochet 2016-01-24 20:07:54 +01:00
parent 9c7231ee75
commit 4beacc4ca0
3 changed files with 33 additions and 11 deletions
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2
src/include/netif/ppp/vj.h
View File

@ -151,7 +151,7 @@ struct vjcompress {
#define VJF_TOSS 1U /* tossing rcvd frames because of input err */
extern void vj_compress_init (struct vjcompress *comp);
extern u8_t vj_compress_tcp (struct vjcompress *comp, struct pbuf *pb);
extern u8_t vj_compress_tcp (struct vjcompress *comp, struct pbuf **pb);
extern void vj_uncompress_err (struct vjcompress *comp);
extern int vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp);
extern int vj_uncompress_tcp (struct pbuf **nb, struct vjcompress *comp);

10
src/netif/ppp/ppp.c
View File

@ -487,15 +487,21 @@ static err_t ppp_netif_output(struct netif *netif, struct pbuf *pb, u16_t protoc
* this is an IP packet.
*/
if (protocol == PPP_IP && pcb->vj_enabled) {
switch (vj_compress_tcp(&pcb->vj_comp, pb)) {
switch (vj_compress_tcp(&pcb->vj_comp, &pb)) {
case TYPE_IP:
/* No change...
protocol = PPP_IP_PROTOCOL; */
protocol = PPP_IP; */
break;
case TYPE_COMPRESSED_TCP:
/* vj_compress_tcp() returns a new allocated pbuf, indicate we should free
* our duplicated pbuf later */
fpb = pb;
protocol = PPP_VJC_COMP;
break;
case TYPE_UNCOMPRESSED_TCP:
/* vj_compress_tcp() returns a new allocated pbuf, indicate we should free
* our duplicated pbuf later */
fpb = pb;
protocol = PPP_VJC_UNCOMP;
break;
default:

32
src/netif/ppp/vj.c
View File

@ -132,9 +132,10 @@ vj_compress_init(struct vjcompress *comp)
* compressed.
*/
u8_t
vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
vj_compress_tcp(struct vjcompress *comp, struct pbuf **pb)
{
struct ip_hdr *ip = (struct ip_hdr *)pb->payload;
struct pbuf *np = *pb;
struct ip_hdr *ip = (struct ip_hdr *)np->payload;
struct cstate *cs = comp->last_cs->cs_next;
u16_t ilen = IPH_HL(ip);
u16_t hlen;
@ -158,7 +159,7 @@ vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
* `compressible' (i.e., ACK isn't set or some other control bit is
* set).
*/
if ((IPH_OFFSET(ip) & PP_HTONS(0x3fff)) || pb->tot_len < 40) {
if ((IPH_OFFSET(ip) & PP_HTONS(0x3fff)) || np->tot_len < 40) {
return (TYPE_IP);
}
th = (struct tcp_hdr *)&((u32_t*)ip)[ilen];
@ -169,11 +170,26 @@ vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
/* Check that the TCP/IP headers are contained in the first buffer. */
hlen = ilen + TCPH_HDRLEN(th);
hlen <<= 2;
if (pb->len < hlen) {
if (np->len < hlen) {
PPPDEBUG(LOG_INFO, ("vj_compress_tcp: header len %d spans buffers\n", hlen));
return (TYPE_IP);
}
/* TCP stack requires that we don't change the packet payload, therefore we copy
* the whole packet before compression. */
np = pbuf_alloc(PBUF_RAW, np->tot_len, PBUF_POOL);
if (!np) {
return (TYPE_IP);
}
if (pbuf_copy(np, *pb) != ERR_OK) {
pbuf_free(np);
return (TYPE_IP);
}
*pb = np;
ip = (struct ip_hdr *)np->payload;
/*
* Packet is compressible -- we're going to send either a
* COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need
@ -371,20 +387,20 @@ vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
if (!comp->compressSlot || comp->last_xmit != cs->cs_id) {
comp->last_xmit = cs->cs_id;
hlen -= deltaS + 4;
if (pbuf_header(pb, -(s16_t)hlen)){
if (pbuf_header(np, -(s16_t)hlen)){
/* Can we cope with this failing? Just assert for now */
LWIP_ASSERT("pbuf_header failed\n", 0);
}
cp = (u8_t*)pb->payload;
cp = (u8_t*)np->payload;
*cp++ = (u8_t)(changes | NEW_C);
*cp++ = cs->cs_id;
} else {
hlen -= deltaS + 3;
if (pbuf_header(pb, -(s16_t)hlen)) {
if (pbuf_header(np, -(s16_t)hlen)) {
/* Can we cope with this failing? Just assert for now */
LWIP_ASSERT("pbuf_header failed\n", 0);
}
cp = (u8_t*)pb->payload;
cp = (u8_t*)np->payload;
*cp++ = (u8_t)changes;
}
*cp++ = (u8_t)(deltaA >> 8);