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/* $NetBSD: in_offload.c,v 1.13 2018/12/12 01:40:20 rin Exp $ */
/*
* Copyright (c)2005, 2006 YAMAMOTO Takashi,
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: in_offload.c,v 1.13 2018/12/12 01:40:20 rin Exp $");
#include <sys/param.h>
#include <sys/mbuf.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/in_offload.h>
/*
* Handle M_CSUM_TSOv4 in software. Split the TCP payload in chunks of
* size MSS, and return mbuf chain consists of them.
*/
struct mbuf *
tcp4_segment(struct mbuf *m, int off)
{
int mss;
int iphlen, thlen;
int hlen, len;
struct ip *ip;
struct tcphdr *th;
uint16_t ipid, phsum;
uint32_t tcpseq;
struct mbuf *hdr = NULL;
struct mbuf *m0 = NULL;
struct mbuf *prev = NULL;
struct mbuf *n, *t;
int nsegs;
KASSERT((m->m_flags & M_PKTHDR) != 0);
KASSERT((m->m_pkthdr.csum_flags & M_CSUM_TSOv4) != 0);
m->m_pkthdr.csum_flags = 0;
len = m->m_pkthdr.len;
KASSERT(len >= off + sizeof(*ip) + sizeof(*th));
hlen = off + sizeof(*ip);
if (m->m_len < hlen) {
m = m_pullup(m, hlen);
if (m == NULL)
goto quit;
}
ip = (void *)(mtod(m, char *) + off);
iphlen = ip->ip_hl * 4;
KASSERT(ip->ip_v == IPVERSION);
KASSERT(iphlen >= sizeof(*ip));
KASSERT(ip->ip_p == IPPROTO_TCP);
ipid = ntohs(ip->ip_id);
hlen = off + iphlen + sizeof(*th);
if (m->m_len < hlen) {
m = m_pullup(m, hlen);
if (m == NULL)
goto quit;
}
th = (void *)(mtod(m, char *) + off + iphlen);
tcpseq = ntohl(th->th_seq);
thlen = th->th_off * 4;
hlen = off + iphlen + thlen;
mss = m->m_pkthdr.segsz;
KASSERT(mss != 0);
KASSERT(len > hlen);
t = m_split(m, hlen, M_NOWAIT);
if (t == NULL)
goto quit;
hdr = m;
m = t;
len -= hlen;
KASSERT(len % mss == 0);
ip = (void *)(mtod(hdr, char *) + off);
ip->ip_len = htons(iphlen + thlen + mss);
phsum = in_cksum_phdr(ip->ip_src.s_addr, ip->ip_dst.s_addr,
htons((uint16_t)(thlen + mss) + IPPROTO_TCP));
for (nsegs = len / mss; nsegs > 0; nsegs--) {
if (nsegs > 1) {
n = m_dup(hdr, 0, hlen, M_NOWAIT);
if (n == NULL)
goto quit;
} else
n = hdr;
KASSERT(n->m_len == hlen); /* XXX */
if (nsegs > 1) {
t = m_split(m, mss, M_NOWAIT);
if (t == NULL) {
m_freem(n);
goto quit;
}
} else
t = m;
m_cat(n, m);
m = t;
KASSERT(n->m_len >= hlen); /* XXX */
if (m0 == NULL)
m0 = n;
if (prev != NULL)
prev->m_nextpkt = n;
n->m_pkthdr.len = hlen + mss;
n->m_nextpkt = NULL; /* XXX */
ip = (void *)(mtod(n, char *) + off);
ip->ip_id = htons(ipid);
ip->ip_sum = 0;
ip->ip_sum = in4_cksum(n, 0, off, iphlen);
th = (void *)(mtod(n, char *) + off + iphlen);
th->th_seq = htonl(tcpseq);
th->th_sum = phsum;
th->th_sum = in4_cksum(n, 0, off + iphlen, thlen + mss);
tcpseq += mss;
ipid++;
prev = n;
}
return m0;
quit:
if (hdr != NULL)
m_freem(hdr);
if (m != NULL)
m_freem(m);
for (m = m0; m != NULL; m = n) {
n = m->m_nextpkt;
m_freem(m);
}
return NULL;
}
int
ip_tso_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa,
struct rtentry *rt)
{
struct mbuf *n;
int error = 0;
m = tcp4_segment(m, 0);
if (m == NULL)
return ENOMEM;
do {
n = m->m_nextpkt;
if (error == 0)
error = ip_if_output(ifp, m, sa, rt);
else
m_freem(m);
m = n;
} while (m != NULL);
return error;
}
/*
* Compute now in software the IP and TCP/UDP checksums. Cancel the
* hardware offloading.
*/
void
in_undefer_cksum(struct mbuf *m, size_t hdrlen, int csum_flags)
{
const size_t iphdrlen = M_CSUM_DATA_IPv4_IPHL(m->m_pkthdr.csum_data);
uint16_t csum;
uint16_t ip_len;
uint16_t *csump;
KASSERT(m->m_flags & M_PKTHDR);
KASSERT((m->m_pkthdr.csum_flags & csum_flags) == csum_flags);
if (__predict_true(hdrlen + sizeof(struct ip) <= m->m_len)) {
struct ip *ip = (struct ip *)(mtod(m, uint8_t *) + hdrlen);
ip_len = ip->ip_len;
csump = &ip->ip_sum;
} else {
const size_t ip_len_offset =
hdrlen + offsetof(struct ip, ip_len);
m_copydata(m, ip_len_offset, sizeof(ip_len), &ip_len);
csump = NULL;
}
ip_len = ntohs(ip_len);
if (csum_flags & M_CSUM_IPv4) {
csum = in4_cksum(m, 0, hdrlen, iphdrlen);
if (csump != NULL) {
*csump = csum;
} else {
const size_t offset = hdrlen +
offsetof(struct ip, ip_sum);
m_copyback(m, offset, sizeof(uint16_t), &csum);
}
}
if (csum_flags & (M_CSUM_UDPv4|M_CSUM_TCPv4)) {
size_t l4offset = hdrlen + iphdrlen;
csum = in4_cksum(m, 0, l4offset, ip_len - iphdrlen);
if (csum == 0 && (csum_flags & M_CSUM_UDPv4) != 0)
csum = 0xffff;
l4offset += M_CSUM_DATA_IPv4_OFFSET(m->m_pkthdr.csum_data);
if (__predict_true(l4offset + sizeof(uint16_t) <= m->m_len)) {
*(uint16_t *)(mtod(m, char *) + l4offset) = csum;
} else {
m_copyback(m, l4offset, sizeof(csum), (void *)&csum);
}
}
m->m_pkthdr.csum_flags ^= csum_flags;
}
/*
* Compute now in software the TCP/UDP checksum. Cancel the hardware
* offloading.
*/
void
in_undefer_cksum_tcpudp(struct mbuf *m)
{
struct ip *ip;
uint16_t csum, offset;
KASSERT((m->m_flags & M_PKTHDR) != 0);
KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_TCPv4|M_CSUM_UDPv4)) != 0);
KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_TCPv6|M_CSUM_UDPv6)) == 0);
ip = mtod(m, struct ip *);
offset = ip->ip_hl << 2;
csum = in4_cksum(m, 0, offset, ntohs(ip->ip_len) - offset);
if (csum == 0 && (m->m_pkthdr.csum_flags & M_CSUM_UDPv4) != 0)
csum = 0xffff;
offset += M_CSUM_DATA_IPv4_OFFSET(m->m_pkthdr.csum_data);
if ((offset + sizeof(uint16_t)) <= m->m_len) {
*(uint16_t *)(mtod(m, char *) + offset) = csum;
} else {
m_copyback(m, offset, sizeof(csum), (void *)&csum);
}
}
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