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In the ip_reass() do packet examination and adjusting before acquiring

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locks and doing lookups.

Sponsored by:	Nginx, Inc.
This commit is contained in:
Gleb Smirnoff 2015-04-09 21:32:32 +00:00
parent 64026fd83c
commit f5746f593c
1 changed files with 35 additions and 34 deletions
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69
sys/netinet/ip_input.c
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@ -938,6 +938,41 @@ ip_reass(struct mbuf *m)
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
/*
* Adjust ip_len to not reflect header,
* convert offset of this to bytes.
*/
ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
if (ip->ip_off & htons(IP_MF)) {
/*
* Make sure that fragments have a data length
* that's a non-zero multiple of 8 bytes.
*/
if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) {
IPSTAT_INC(ips_toosmall); /* XXX */
IPSTAT_INC(ips_fragdropped);
m_freem(m);
return (NULL);
}
m->m_flags |= M_IP_FRAG;
} else
m->m_flags &= ~M_IP_FRAG;
ip->ip_off = htons(ntohs(ip->ip_off) << 3);
/*
* Attempt reassembly; if it succeeds, proceed.
* ip_reass() will return a different mbuf.
*/
IPSTAT_INC(ips_fragments);
m->m_pkthdr.PH_loc.ptr = ip;
/*
* Presence of header sizes in mbufs
* would confuse code below.
*/
m->m_data += hlen;
m->m_len -= hlen;
hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
head = &V_ipq[hash].head;
IPQ_LOCK(hash);
@ -979,40 +1014,6 @@ ip_reass(struct mbuf *m)
}
found:
/*
* Adjust ip_len to not reflect header,
* convert offset of this to bytes.
*/
ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
if (ip->ip_off & htons(IP_MF)) {
/*
* Make sure that fragments have a data length
* that's a non-zero multiple of 8 bytes.
*/
if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) {
IPSTAT_INC(ips_toosmall); /* XXX */
goto dropfrag;
}
m->m_flags |= M_IP_FRAG;
} else
m->m_flags &= ~M_IP_FRAG;
ip->ip_off = htons(ntohs(ip->ip_off) << 3);
/*
* Attempt reassembly; if it succeeds, proceed.
* ip_reass() will return a different mbuf.
*/
IPSTAT_INC(ips_fragments);
m->m_pkthdr.PH_loc.ptr = ip;
/* Previous ip_reass() started here. */
/*
* Presence of header sizes in mbufs
* would confuse code below.
*/
m->m_data += hlen;
m->m_len -= hlen;
/*
* If first fragment to arrive, create a reassembly queue.
*/