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Fix the checksum computation for UDPLite/IPv6. This requires the

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usage of a function computing the checksum only over a part of the function.
Therefore introduce in6_cksum_partial() and implement in6_cksum() based
on that.
While there, ensure that the UDPLite packet contains at least enough bytes
to contain the header.

Reviewed by: kevlo
MFC after: 3 days
This commit is contained in:
Michael Tuexen 2014-10-02 10:32:24 +00:00
parent 759489f9e2
commit 76b96fbc9e
3 changed files with 30 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/netinet6/in6.h
View File

@ -647,6 +647,8 @@ struct ip6_hdr;
int in6_cksum_pseudo(struct ip6_hdr *, uint32_t, uint8_t, uint16_t);
int in6_cksum(struct mbuf *, u_int8_t, u_int32_t, u_int32_t);
int in6_cksum_partial(struct mbuf *, u_int8_t, u_int32_t, u_int32_t,
u_int32_t);
int in6_localaddr(struct in6_addr *);
int in6_localip(struct in6_addr *);
int in6_addrscope(const struct in6_addr *);

28
sys/netinet6/in6_cksum.c
View File

@ -145,9 +145,11 @@ in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
* off is an offset where TCP/UDP/ICMP6 header starts.
* len is a total length of a transport segment.
* (e.g. TCP header + TCP payload)
* cov is the number of bytes to be taken into account for the checksum
*/
int
in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
u_int32_t len, u_int32_t cov)
{
struct ip6_hdr *ip6;
u_int16_t *w, scope;
@ -215,9 +217,9 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
}
w = (u_int16_t *)(mtod(m, u_char *) + off);
mlen = m->m_len - off;
if (len < mlen)
mlen = len;
len -= mlen;
if (cov < mlen)
mlen = cov;
cov -= mlen;
/*
* Force to even boundary.
*/
@ -273,7 +275,7 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
* Lastly calculate a summary of the rest of mbufs.
*/
for (;m && len; m = m->m_next) {
for (;m && cov; m = m->m_next) {
if (m->m_len == 0)
continue;
w = mtod(m, u_int16_t *);
@ -290,12 +292,12 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
sum += s_util.s;
w = (u_int16_t *)((char *)w + 1);
mlen = m->m_len - 1;
len--;
cov--;
} else
mlen = m->m_len;
if (len < mlen)
mlen = len;
len -= mlen;
if (cov < mlen)
mlen = cov;
cov -= mlen;
/*
* Force to even boundary.
*/
@ -343,7 +345,7 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
} else if (mlen == -1)
s_util.c[0] = *(char *)w;
}
if (len)
if (cov)
panic("in6_cksum: out of data");
if (mlen == -1) {
/* The last mbuf has odd # of bytes. Follow the
@ -355,3 +357,9 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
REDUCE;
return (~sum & 0xffff);
}
int
in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
{
return (in6_cksum_partial(m, nxt, off, len, len));
}

15
sys/netinet6/udp6_usrreq.c
View File

@ -227,11 +227,16 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
nxt = ip6->ip6_nxt;
cscov_partial = (nxt == IPPROTO_UDPLITE) ? 1 : 0;
if (nxt == IPPROTO_UDPLITE && (ulen == 0 || ulen == plen)) {
if (nxt == IPPROTO_UDPLITE) {
/* Zero means checksum over the complete packet. */
if (ulen == 0)
ulen = plen;
cscov_partial = 0;
if (ulen == plen)
cscov_partial = 0;
if ((ulen < sizeof(struct udphdr)) || (ulen > plen)) {
/* XXX: What is the right UDPLite MIB counter? */
goto badunlocked;
}
}
if (nxt == IPPROTO_UDP && plen != ulen) {
UDPSTAT_INC(udps_badlen);
@ -257,7 +262,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
m->m_pkthdr.csum_data);
uh_sum ^= 0xffff;
} else
uh_sum = in6_cksum(m, nxt, off, ulen);
uh_sum = in6_cksum_partial(m, nxt, off, plen, ulen);
if (uh_sum != 0) {
UDPSTAT_INC(udps_badsum);
@ -844,8 +849,8 @@ udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
ip6->ip6_dst = *faddr;
if (cscov_partial) {
if ((udp6->uh_sum = in6_cksum(m, 0,
sizeof(struct ip6_hdr), cscov)) == 0)
if ((udp6->uh_sum = in6_cksum_partial(m, nxt,
sizeof(struct ip6_hdr), plen, cscov)) == 0)
udp6->uh_sum = 0xffff;
} else {
udp6->uh_sum = in6_cksum_pseudo(ip6, plen, nxt, 0);