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* Check for ip_id zero senders and low cost update of zero ip_id.

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bg- 2007-02-01 14:04:06 +00:00
parent 85fd100263
commit 7d5a6d6558
1 changed files with 13 additions and 1 deletions
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14
core/dev/slip.c
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@ -29,7 +29,7 @@
*
* This file is part of the Contiki operating system.
*
* @(#)$Id: slip.c,v 1.3 2007/01/23 12:30:12 bg- Exp $
* @(#)$Id: slip.c,v 1.4 2007/02/01 14:04:06 bg- Exp $
*/
@ -236,6 +236,18 @@ PROCESS_THREAD(slip_process, ev, data)
} else if(uip_len > 0
&& uip_len == (((u16_t)(BUF->len[0]) << 8) + BUF->len[1])
&& uip_ipchksum() == 0xffff) {
#define IP_DF 0x40
if(BUF->ipid[0] == 0 && BUF->ipid[1] == 0 && BUF->ipoffset[0] & IP_DF) {
static u16_t ip_id;
u16_t nid = ip_id++;
BUF->ipid[0] = nid >> 8;
BUF->ipid[1] = nid;
nid = htons(nid);
nid = ~nid; /* negate */
BUF->ipchksum += nid; /* add */
if (BUF->ipchksum < nid) /* 1-complement overflow? */
BUF->ipchksum++;
}
tcpip_input();
} else {
uip_len = 0;