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UDP Lite: corrected the use of chksum_len (based on RFC3828: if it's 0, create checksum over the complete packet. On RX, if it's < 8 (and not 0), discard the packet. Also removed the duplicate 'udphdr->chksum = 0' for both UDP & UDP Lite.

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This commit is contained in:
goldsimon 2007-06-11 18:03:57 +00:00
parent 1d7caed340
commit 2f293d53ba
2 changed files with 38 additions and 6 deletions
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6
CHANGELOG
View File

@ -196,6 +196,12 @@ HISTORY
++ Bug fixes:
2007-06-11 Simon Goldschmidt
* udp.c: UDP Lite: corrected the use of chksum_len (based on RFC3828: if it's 0,
create checksum over the complete packet. On RX, if it's < 8 (and not 0),
discard the packet. Also removed the duplicate 'udphdr->chksum = 0' for both
UDP & UDP Lite.
2007-06-11 Srinivas Gollakota & Oleg Tyshev
* tcp_out.c: Fix for bug #20075 : "A problem with keep-alive timer and TCP flags"
where TCP flags wasn't initialized in tcp_keepalive.

38
src/core/udp.c
View File

@ -182,9 +182,25 @@ udp_input(struct pbuf *p, struct netif *inp)
if (IPH_PROTO(iphdr) == IP_PROTO_UDPLITE) {
/* Do the UDP Lite checksum */
#if CHECKSUM_CHECK_UDP
u16_t chklen = ntohs(udphdr->len);
if (chklen < sizeof(struct udp_hdr)) {
if (chklen == 0) {
/* For UDP-Lite, checksum length of 0 means checksum
over the complete packet (See RFC 3828 chap. 3.1) */
chklen = p->tot_len;
} else {
/* At least the UDP-Lite header must be covered by the
checksum! (Again, see RFC 3828 chap. 3.1) */
UDP_STATS_INC(udp.chkerr);
UDP_STATS_INC(udp.drop);
snmp_inc_udpinerrors();
pbuf_free(p);
goto end;
}
}
if (inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src),
(struct ip_addr *)&(iphdr->dest),
IP_PROTO_UDPLITE, ntohs(udphdr->len)) != 0) {
IP_PROTO_UDPLITE, chklen) != 0) {
LWIP_DEBUGF(UDP_DEBUG | 2,
("udp_input: UDP Lite datagram discarded due to failing checksum\n"));
UDP_STATS_INC(udp.chkerr);
@ -395,9 +411,23 @@ udp_send(struct udp_pcb *pcb, struct pbuf *p)
#if LWIP_UDPLITE
/* UDP Lite protocol? */
if (pcb->flags & UDP_FLAGS_UDPLITE) {
u16_t chklen;
LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE packet length %"U16_F"\n", q->tot_len));
/* set UDP message length in UDP header */
udphdr->len = htons(pcb->chksum_len);
chklen = pcb->chksum_len;
if (chklen < sizeof(struct udp_hdr)) {
if (chklen != 0) {
LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE pcb->chksum_len is illegal: %"U16_F"\n", chklen));
}
/* For UDP-Lite, checksum length of 0 means checksum
over the complete packet. (See RFC 3828 chap. 3.1)
At least the UDP-Lite header must be covered by the
checksum, therefore, if chksum_len has an illegal
value, we generate the checksum over the complete
packet to be safe. */
chklen = p->tot_len;
}
udphdr->len = htons(chklen);
/* calculate checksum */
#if CHECKSUM_GEN_UDP
udphdr->chksum = inet_chksum_pseudo(q, src_ip, &(pcb->remote_ip),
@ -405,8 +435,6 @@ udp_send(struct udp_pcb *pcb, struct pbuf *p)
/* chksum zero must become 0xffff, as zero means 'no checksum' */
if (udphdr->chksum == 0x0000)
udphdr->chksum = 0xffff;
#else /* CHECKSUM_CHECK_UDP */
udphdr->chksum = 0x0000;
#endif /* CHECKSUM_CHECK_UDP */
/* output to IP */
LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,IP_PROTO_UDPLITE,)\n"));
@ -423,8 +451,6 @@ udp_send(struct udp_pcb *pcb, struct pbuf *p)
/* chksum zero must become 0xffff, as zero means 'no checksum' */
if (udphdr->chksum == 0x0000) udphdr->chksum = 0xffff;
}
#else /* CHECKSUM_CHECK_UDP */
udphdr->chksum = 0x0000;
#endif /* CHECKSUM_CHECK_UDP */
LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP checksum 0x%04"X16_F"\n", udphdr->chksum));
LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,IP_PROTO_UDP,)\n"));