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author | bz <bz@FreeBSD.org> | 2012-05-24 18:05:10 +0000 |
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committer | bz <bz@FreeBSD.org> | 2012-05-24 18:05:10 +0000 |
commit | 0a74a9f5597ed88e7f94539d3ec49ed7ed18b66b (patch) | |
tree | 4f5cf34fa9a6731008e39e1ec9776428171f4df1 /sys/netinet6/in6_cksum.c | |
parent | 1759916fa95d3f268c693fce26434f39be74be46 (diff) | |
download | FreeBSD-src-0a74a9f5597ed88e7f94539d3ec49ed7ed18b66b.zip FreeBSD-src-0a74a9f5597ed88e7f94539d3ec49ed7ed18b66b.tar.gz |
MFp4 bz_ipv6_fast:
Optimize in6_cksum(), re-ordering work and limiting variable
initialization, removing a bzero() for mostly re-initialized
struct values, making use of the newly introduced in6_getscope(),
as well as converting an if/panic to a KASSERT().
Sponsored by: The FreeBSD Foundation
Sponsored by: iXsystems
Reviewed by: gnn (as part of the whole)
MFC After: 3 days
Diffstat (limited to 'sys/netinet6/in6_cksum.c')
-rw-r--r-- | sys/netinet6/in6_cksum.c | 58 |
1 files changed, 27 insertions, 31 deletions
diff --git a/sys/netinet6/in6_cksum.c b/sys/netinet6/in6_cksum.c index 9cb97bd..034848b 100644 --- a/sys/netinet6/in6_cksum.c +++ b/sys/netinet6/in6_cksum.c @@ -89,12 +89,10 @@ __FBSDID("$FreeBSD$"); int in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len) { - u_int16_t *w; - int sum = 0; - int mlen = 0; - int byte_swapped = 0; struct ip6_hdr *ip6; - struct in6_addr in6; + u_int16_t *w, scope; + int byte_swapped, mlen; + int sum; union { u_int16_t phs[4]; struct { @@ -112,42 +110,38 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len) u_int32_t l; } l_util; - /* sanity check */ - if (m->m_pkthdr.len < off + len) { - panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)", - m->m_pkthdr.len, off, len); - } - - bzero(&uph, sizeof(uph)); + /* Sanity check. */ + KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+" + "len(%d)", __func__, m->m_pkthdr.len, off, len)); /* * First create IP6 pseudo header and calculate a summary. */ - ip6 = mtod(m, struct ip6_hdr *); uph.ph.ph_len = htonl(len); + uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0; uph.ph.ph_nxt = nxt; - /* - * IPv6 source address. - * XXX: we'd like to avoid copying the address, but we can't due to - * the possibly embedded scope zone ID. - */ - in6 = ip6->ip6_src; - in6_clearscope(&in6); - w = (u_int16_t *)&in6; + /* Payload length and upper layer identifier. */ + sum = uph.phs[0]; sum += uph.phs[1]; + sum += uph.phs[2]; sum += uph.phs[3]; + + ip6 = mtod(m, struct ip6_hdr *); + + /* IPv6 source address. */ + scope = in6_getscope(&ip6->ip6_src); + w = (u_int16_t *)&ip6->ip6_src; sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; + if (scope != 0) + sum -= scope; - /* IPv6 destination address */ - in6 = ip6->ip6_dst; - in6_clearscope(&in6); - w = (u_int16_t *)&in6; + /* IPv6 destination address. */ + scope = in6_getscope(&ip6->ip6_dst); + w = (u_int16_t *)&ip6->ip6_dst; sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; - - /* Payload length and upper layer identifier */ - sum += uph.phs[0]; sum += uph.phs[1]; - sum += uph.phs[2]; sum += uph.phs[3]; + if (scope != 0) + sum -= scope; /* * Secondly calculate a summary of the first mbuf excluding offset. @@ -167,14 +161,16 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len) /* * Force to even boundary. */ - if ((1 & (long) w) && (mlen > 0)) { + if ((1 & (long)w) && (mlen > 0)) { REDUCE; sum <<= 8; s_util.c[0] = *(u_char *)w; w = (u_int16_t *)((char *)w + 1); mlen--; byte_swapped = 1; - } + } else + byte_swapped = 0; + /* * Unroll the loop to make overhead from * branches &c small. |