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| author | Gleb Smirnoff <glebius@FreeBSD.org> | 2015-04-10 06:55:43 +0000 |
|---|---|---|
| committer | Gleb Smirnoff <glebius@FreeBSD.org> | 2015-04-10 06:55:43 +0000 |
| commit | c047fd1b9982ac28a57e71698b147acb65707d68 (patch) | |
| tree | 945c3dfb3476347c9c0bce1766e89a2a71d05623 /sys | |
| parent | 1dbefcc00d646c7a1cefd96bf03266ef9487e61e (diff) | |
| download | src-c047fd1b9982ac28a57e71698b147acb65707d68.tar.gz src-c047fd1b9982ac28a57e71698b147acb65707d68.zip | |
o Use Jenkins hash. With previous hash, for a single source IP address and
sequential IP ID case (e.g. ping -f), distribution fell into 8-10 buckets
out of 64. With Jenkins hash, distribution is even.
o Add random seed to the hash.
Sponsored by: Nginx, Inc.
Notes
Notes:
svn path=/head/; revision=281352
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/netinet/ip_reass.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/sys/netinet/ip_reass.c b/sys/netinet/ip_reass.c index a7c5d38eb6d4..73262fec7776 100644 --- a/sys/netinet/ip_reass.c +++ b/sys/netinet/ip_reass.c @@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/systm.h> #include <sys/eventhandler.h> +#include <sys/hash.h> #include <sys/mbuf.h> #include <sys/malloc.h> #include <sys/lock.h> @@ -64,8 +65,6 @@ SYSCTL_DECL(_net_inet_ip); #define IPREASS_NHASH_LOG2 6 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) #define IPREASS_HMASK (IPREASS_NHASH - 1) -#define IPREASS_HASH(x,y) \ - (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) struct ipqbucket { TAILQ_HEAD(ipqhead, ipq) head; @@ -74,6 +73,8 @@ struct ipqbucket { static VNET_DEFINE(struct ipqbucket, ipq[IPREASS_NHASH]); #define V_ipq VNET(ipq) +static VNET_DEFINE(uint32_t, ipq_hashseed); +#define V_ipq_hashseed VNET(ipq_hashseed) #define IPQ_LOCK(i) mtx_lock(&V_ipq[i].lock) #define IPQ_TRYLOCK(i) mtx_trylock(&V_ipq[i].lock) @@ -146,7 +147,7 @@ ip_reass(struct mbuf *m) struct ipqhead *head; int i, hlen, next; u_int8_t ecn, ecn0; - u_short hash; + uint32_t hash; #ifdef RSS uint32_t rss_hash, rss_type; #endif @@ -200,7 +201,8 @@ ip_reass(struct mbuf *m) m->m_data += hlen; m->m_len -= hlen; - hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); + hash = ip->ip_src.s_addr ^ ip->ip_id; + hash = jenkins_hash32(&hash, 1, V_ipq_hashseed) & IPREASS_HMASK; head = &V_ipq[hash].head; IPQ_LOCK(hash); @@ -465,6 +467,7 @@ ipreass_init(void) mtx_init(&V_ipq[i].lock, "IP reassembly", NULL, MTX_DEF | MTX_DUPOK); } + V_ipq_hashseed = arc4random(); V_maxfragsperpacket = 16; V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); |