Author: glebius
Date: Thu Apr 9 21:32:32 2015
New Revision: 281334
URL: https://svnweb.freebsd.org/changeset/base/281334
Log:
In the ip_reass() do packet examination and adjusting before acquiring
locks and doing lookups.
Sponsored by: Nginx, Inc.
Modified:
head/sys/netinet/ip_input.c
Modified: head/sys/netinet/ip_input.c
==============================================================================
--- head/sys/netinet/ip_input.c Thu Apr 9 21:30:11 2015 (r281333)
+++ head/sys/netinet/ip_input.c Thu Apr 9 21:32:32 2015 (r281334)
@@ -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);
@@ -980,40 +1015,6 @@ 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.
*/
if (fp == NULL) {
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