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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/net/ipv6/ip6_output.c

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37 KiB
C
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/*
* IPv6 output functions
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* $Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $
*
* Based on linux/net/ipv4/ip_output.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Changes:
* A.N.Kuznetsov : airthmetics in fragmentation.
* extension headers are implemented.
* route changes now work.
* ip6_forward does not confuse sniffers.
* etc.
*
* H. von Brand : Added missing #include <linux/string.h>
* Imran Patel : frag id should be in NBO
* Kazunori MIYAZAWA @USAGI
* : add ip6_append_data and related functions
* for datagram xmit
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/in6.h>
#include <linux/tcp.h>
#include <linux/route.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <net/sock.h>
#include <net/snmp.h>
#include <net/ipv6.h>
#include <net/ndisc.h>
#include <net/protocol.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/rawv6.h>
#include <net/icmp.h>
#include <net/xfrm.h>
#include <net/checksum.h>
static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr)
{
static u32 ipv6_fragmentation_id = 1;
static DEFINE_SPINLOCK(ip6_id_lock);
spin_lock_bh(&ip6_id_lock);
fhdr->identification = htonl(ipv6_fragmentation_id);
if (++ipv6_fragmentation_id == 0)
ipv6_fragmentation_id = 1;
spin_unlock_bh(&ip6_id_lock);
}
int __ip6_local_out(struct sk_buff *skb)
{
int len;
len = skb->len - sizeof(struct ipv6hdr);
if (len > IPV6_MAXPLEN)
len = 0;
ipv6_hdr(skb)->payload_len = htons(len);
return nf_hook(PF_INET6, NF_INET_LOCAL_OUT, skb, NULL, skb->dst->dev,
dst_output);
}
int ip6_local_out(struct sk_buff *skb)
{
int err;
err = __ip6_local_out(skb);
if (likely(err == 1))
err = dst_output(skb);
return err;
}
EXPORT_SYMBOL_GPL(ip6_local_out);
static int ip6_output_finish(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
if (dst->hh)
return neigh_hh_output(dst->hh, skb);
else if (dst->neighbour)
return dst->neighbour->output(skb);
IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
kfree_skb(skb);
return -EINVAL;
}
/* dev_loopback_xmit for use with netfilter. */
static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
{
skb_reset_mac_header(newskb);
__skb_pull(newskb, skb_network_offset(newskb));
newskb->pkt_type = PACKET_LOOPBACK;
newskb->ip_summed = CHECKSUM_UNNECESSARY;
BUG_TRAP(newskb->dst);
netif_rx(newskb);
return 0;
}
static int ip6_output2(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
struct net_device *dev = dst->dev;
skb->protocol = htons(ETH_P_IPV6);
skb->dev = dev;
if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL;
struct inet6_dev *idev = ip6_dst_idev(skb->dst);
if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&
ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
&ipv6_hdr(skb)->saddr)) {
struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
/* Do not check for IFF_ALLMULTI; multicast routing
is not supported in any case.
*/
if (newskb)
NF_HOOK(PF_INET6, NF_INET_POST_ROUTING, newskb,
NULL, newskb->dev,
ip6_dev_loopback_xmit);
if (ipv6_hdr(skb)->hop_limit == 0) {
IP6_INC_STATS(idev, IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
return 0;
}
}
IP6_INC_STATS(idev, IPSTATS_MIB_OUTMCASTPKTS);
}
return NF_HOOK(PF_INET6, NF_INET_POST_ROUTING, skb, NULL, skb->dev,
ip6_output_finish);
}
static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
{
struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
return (np && np->pmtudisc == IPV6_PMTUDISC_PROBE) ?
skb->dst->dev->mtu : dst_mtu(skb->dst);
}
int ip6_output(struct sk_buff *skb)
{
if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
dst_allfrag(skb->dst))
return ip6_fragment(skb, ip6_output2);
else
return ip6_output2(skb);
}
/*
* xmit an sk_buff (used by TCP)
*/
int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
struct ipv6_txoptions *opt, int ipfragok)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct in6_addr *first_hop = &fl->fl6_dst;
struct dst_entry *dst = skb->dst;
struct ipv6hdr *hdr;
u8 proto = fl->proto;
int seg_len = skb->len;
int hlimit, tclass;
u32 mtu;
if (opt) {
unsigned int head_room;
/* First: exthdrs may take lots of space (~8K for now)
MAX_HEADER is not enough.
*/
head_room = opt->opt_nflen + opt->opt_flen;
seg_len += head_room;
head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
if (skb_headroom(skb) < head_room) {
struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
if (skb2 == NULL) {
IP6_INC_STATS(ip6_dst_idev(skb->dst),
IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
return -ENOBUFS;
}
kfree_skb(skb);
skb = skb2;
if (sk)
skb_set_owner_w(skb, sk);
}
if (opt->opt_flen)
ipv6_push_frag_opts(skb, opt, &proto);
if (opt->opt_nflen)
ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
}
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
hdr = ipv6_hdr(skb);
/*
* Fill in the IPv6 header
*/
hlimit = -1;
if (np)
hlimit = np->hop_limit;
if (hlimit < 0)
hlimit = dst_metric(dst, RTAX_HOPLIMIT);
if (hlimit < 0)
hlimit = ipv6_get_hoplimit(dst->dev);
tclass = -1;
if (np)
tclass = np->tclass;
if (tclass < 0)
tclass = 0;
*(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel;
hdr->payload_len = htons(seg_len);
hdr->nexthdr = proto;
hdr->hop_limit = hlimit;
ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
ipv6_addr_copy(&hdr->daddr, first_hop);
skb->priority = sk->sk_priority;
mtu = dst_mtu(dst);
if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) {
IP6_INC_STATS(ip6_dst_idev(skb->dst),
IPSTATS_MIB_OUTREQUESTS);
return NF_HOOK(PF_INET6, NF_INET_LOCAL_OUT, skb, NULL, dst->dev,
dst_output);
}
if (net_ratelimit())
printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n");
skb->dev = dst->dev;
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return -EMSGSIZE;
}
EXPORT_SYMBOL(ip6_xmit);
/*
* To avoid extra problems ND packets are send through this
* routine. It's code duplication but I really want to avoid
* extra checks since ipv6_build_header is used by TCP (which
* is for us performance critical)
*/
int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev,
struct in6_addr *saddr, struct in6_addr *daddr,
int proto, int len)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct ipv6hdr *hdr;
int totlen;
skb->protocol = htons(ETH_P_IPV6);
skb->dev = dev;
totlen = len + sizeof(struct ipv6hdr);
skb_reset_network_header(skb);
skb_put(skb, sizeof(struct ipv6hdr));
hdr = ipv6_hdr(skb);
*(__be32*)hdr = htonl(0x60000000);
hdr->payload_len = htons(len);
hdr->nexthdr = proto;
hdr->hop_limit = np->hop_limit;
ipv6_addr_copy(&hdr->saddr, saddr);
ipv6_addr_copy(&hdr->daddr, daddr);
return 0;
}
static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
{
struct ip6_ra_chain *ra;
struct sock *last = NULL;
read_lock(&ip6_ra_lock);
for (ra = ip6_ra_chain; ra; ra = ra->next) {
struct sock *sk = ra->sk;
if (sk && ra->sel == sel &&
(!sk->sk_bound_dev_if ||
sk->sk_bound_dev_if == skb->dev->ifindex)) {
if (last) {
struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
if (skb2)
rawv6_rcv(last, skb2);
}
last = sk;
}
}
if (last) {
rawv6_rcv(last, skb);
read_unlock(&ip6_ra_lock);
return 1;
}
read_unlock(&ip6_ra_lock);
return 0;
}
static int ip6_forward_proxy_check(struct sk_buff *skb)
{
struct ipv6hdr *hdr = ipv6_hdr(skb);
u8 nexthdr = hdr->nexthdr;
int offset;
if (ipv6_ext_hdr(nexthdr)) {
offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr);
if (offset < 0)
return 0;
} else
offset = sizeof(struct ipv6hdr);
if (nexthdr == IPPROTO_ICMPV6) {
struct icmp6hdr *icmp6;
if (!pskb_may_pull(skb, (skb_network_header(skb) +
offset + 1 - skb->data)))
return 0;
icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
switch (icmp6->icmp6_type) {
case NDISC_ROUTER_SOLICITATION:
case NDISC_ROUTER_ADVERTISEMENT:
case NDISC_NEIGHBOUR_SOLICITATION:
case NDISC_NEIGHBOUR_ADVERTISEMENT:
case NDISC_REDIRECT:
/* For reaction involving unicast neighbor discovery
* message destined to the proxied address, pass it to
* input function.
*/
return 1;
default:
break;
}
}
/*
* The proxying router can't forward traffic sent to a link-local
* address, so signal the sender and discard the packet. This
* behavior is clarified by the MIPv6 specification.
*/
if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
dst_link_failure(skb);
return -1;
}
return 0;
}
static inline int ip6_forward_finish(struct sk_buff *skb)
{
return dst_output(skb);
}
int ip6_forward(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
struct ipv6hdr *hdr = ipv6_hdr(skb);
struct inet6_skb_parm *opt = IP6CB(skb);
if (ipv6_devconf.forwarding == 0)
goto error;
if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
goto drop;
}
skb_forward_csum(skb);
/*
* We DO NOT make any processing on
* RA packets, pushing them to user level AS IS
* without ane WARRANTY that application will be able
* to interpret them. The reason is that we
* cannot make anything clever here.
*
* We are not end-node, so that if packet contains
* AH/ESP, we cannot make anything.
* Defragmentation also would be mistake, RA packets
* cannot be fragmented, because there is no warranty
* that different fragments will go along one path. --ANK
*/
if (opt->ra) {
u8 *ptr = skb_network_header(skb) + opt->ra;
if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
return 0;
}
/*
* check and decrement ttl
*/
if (hdr->hop_limit <= 1) {
/* Force OUTPUT device used as source address */
skb->dev = dst->dev;
icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
0, skb->dev);
IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
kfree_skb(skb);
return -ETIMEDOUT;
}
/* XXX: idev->cnf.proxy_ndp? */
if (ipv6_devconf.proxy_ndp &&
pneigh_lookup(&nd_tbl, &hdr->daddr, skb->dev, 0)) {
int proxied = ip6_forward_proxy_check(skb);
if (proxied > 0)
return ip6_input(skb);
else if (proxied < 0) {
IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
goto drop;
}
}
if (!xfrm6_route_forward(skb)) {
IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
goto drop;
}
dst = skb->dst;
/* IPv6 specs say nothing about it, but it is clear that we cannot
send redirects to source routed frames.
We don't send redirects to frames decapsulated from IPsec.
*/
if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0 &&
!skb->sp) {
struct in6_addr *target = NULL;
struct rt6_info *rt;
struct neighbour *n = dst->neighbour;
/*
* incoming and outgoing devices are the same
* send a redirect.
*/
rt = (struct rt6_info *) dst;
if ((rt->rt6i_flags & RTF_GATEWAY))
target = (struct in6_addr*)&n->primary_key;
else
target = &hdr->daddr;
/* Limit redirects both by destination (here)
and by source (inside ndisc_send_redirect)
*/
if (xrlim_allow(dst, 1*HZ))
ndisc_send_redirect(skb, n, target);
} else {
int addrtype = ipv6_addr_type(&hdr->saddr);
/* This check is security critical. */
if (addrtype & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK))
goto error;
if (addrtype & IPV6_ADDR_LINKLOCAL) {
icmpv6_send(skb, ICMPV6_DEST_UNREACH,
ICMPV6_NOT_NEIGHBOUR, 0, skb->dev);
goto error;
}
}
if (skb->len > dst_mtu(dst)) {
/* Again, force OUTPUT device used as source address */
skb->dev = dst->dev;
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);
IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return -EMSGSIZE;
}
if (skb_cow(skb, dst->dev->hard_header_len)) {
IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
goto drop;
}
hdr = ipv6_hdr(skb);
/* Mangling hops number delayed to point after skb COW */
hdr->hop_limit--;
IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
return NF_HOOK(PF_INET6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
ip6_forward_finish);
error:
IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
drop:
kfree_skb(skb);
return -EINVAL;
}
static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
{
to->pkt_type = from->pkt_type;
to->priority = from->priority;
to->protocol = from->protocol;
dst_release(to->dst);
to->dst = dst_clone(from->dst);
to->dev = from->dev;
to->mark = from->mark;
#ifdef CONFIG_NET_SCHED
to->tc_index = from->tc_index;
#endif
nf_copy(to, from);
#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
to->nf_trace = from->nf_trace;
#endif
skb_copy_secmark(to, from);
}
int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
{
u16 offset = sizeof(struct ipv6hdr);
struct ipv6_opt_hdr *exthdr =
(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
unsigned int packet_len = skb->tail - skb->network_header;
int found_rhdr = 0;
*nexthdr = &ipv6_hdr(skb)->nexthdr;
while (offset + 1 <= packet_len) {
switch (**nexthdr) {
case NEXTHDR_HOP:
break;
case NEXTHDR_ROUTING:
found_rhdr = 1;
break;
case NEXTHDR_DEST:
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
break;
#endif
if (found_rhdr)
return offset;
break;
default :
return offset;
}
offset += ipv6_optlen(exthdr);
*nexthdr = &exthdr->nexthdr;
exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
offset);
}
return offset;
}
EXPORT_SYMBOL_GPL(ip6_find_1stfragopt);
static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
{
struct net_device *dev;
struct sk_buff *frag;
struct rt6_info *rt = (struct rt6_info*)skb->dst;
struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
struct ipv6hdr *tmp_hdr;
struct frag_hdr *fh;
unsigned int mtu, hlen, left, len;
__be32 frag_id = 0;
int ptr, offset = 0, err=0;
u8 *prevhdr, nexthdr = 0;
dev = rt->u.dst.dev;
hlen = ip6_find_1stfragopt(skb, &prevhdr);
nexthdr = *prevhdr;
mtu = ip6_skb_dst_mtu(skb);
/* We must not fragment if the socket is set to force MTU discovery
* or if the skb it not generated by a local socket. (This last
* check should be redundant, but it's free.)
*/
if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) {
skb->dev = skb->dst->dev;
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return -EMSGSIZE;
}
if (np && np->frag_size < mtu) {
if (np->frag_size)
mtu = np->frag_size;
}
mtu -= hlen + sizeof(struct frag_hdr);
if (skb_shinfo(skb)->frag_list) {
int first_len = skb_pagelen(skb);
if (first_len - hlen > mtu ||
((first_len - hlen) & 7) ||
skb_cloned(skb))
goto slow_path;
for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
/* Correct geometry. */
if (frag->len > mtu ||
((frag->len & 7) && frag->next) ||
skb_headroom(frag) < hlen)
goto slow_path;
/* Partially cloned skb? */
if (skb_shared(frag))
goto slow_path;
BUG_ON(frag->sk);
if (skb->sk) {
sock_hold(skb->sk);
frag->sk = skb->sk;
frag->destructor = sock_wfree;
skb->truesize -= frag->truesize;
}
}
err = 0;
offset = 0;
frag = skb_shinfo(skb)->frag_list;
skb_shinfo(skb)->frag_list = NULL;
/* BUILD HEADER */
*prevhdr = NEXTHDR_FRAGMENT;
tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
if (!tmp_hdr) {
IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
return -ENOMEM;
}
__skb_pull(skb, hlen);
fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
__skb_push(skb, hlen);
skb_reset_network_header(skb);
memcpy(skb_network_header(skb), tmp_hdr, hlen);
ipv6_select_ident(skb, fh);
fh->nexthdr = nexthdr;
fh->reserved = 0;
fh->frag_off = htons(IP6_MF);
frag_id = fh->identification;
first_len = skb_pagelen(skb);
skb->data_len = first_len - skb_headlen(skb);
skb->len = first_len;
ipv6_hdr(skb)->payload_len = htons(first_len -
sizeof(struct ipv6hdr));
dst_hold(&rt->u.dst);
for (;;) {
/* Prepare header of the next frame,
* before previous one went down. */
if (frag) {
frag->ip_summed = CHECKSUM_NONE;
skb_reset_transport_header(frag);
fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
__skb_push(frag, hlen);
skb_reset_network_header(frag);
memcpy(skb_network_header(frag), tmp_hdr,
hlen);
offset += skb->len - hlen - sizeof(struct frag_hdr);
fh->nexthdr = nexthdr;
fh->reserved = 0;
fh->frag_off = htons(offset);
if (frag->next != NULL)
fh->frag_off |= htons(IP6_MF);
fh->identification = frag_id;
ipv6_hdr(frag)->payload_len =
htons(frag->len -
sizeof(struct ipv6hdr));
ip6_copy_metadata(frag, skb);
}
err = output(skb);
if(!err)
IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGCREATES);
if (err || !frag)
break;
skb = frag;
frag = skb->next;
skb->next = NULL;
}
kfree(tmp_hdr);
if (err == 0) {
IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGOKS);
dst_release(&rt->u.dst);
return 0;
}
while (frag) {
skb = frag->next;
kfree_skb(frag);
frag = skb;
}
IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGFAILS);
dst_release(&rt->u.dst);
return err;
}
slow_path:
left = skb->len - hlen; /* Space per frame */
ptr = hlen; /* Where to start from */
/*
* Fragment the datagram.
*/
*prevhdr = NEXTHDR_FRAGMENT;
/*
* Keep copying data until we run out.
*/
while(left > 0) {
len = left;
/* IF: it doesn't fit, use 'mtu' - the data space left */
if (len > mtu)
len = mtu;
/* IF: we are not sending upto and including the packet end
then align the next start on an eight byte boundary */
if (len < left) {
len &= ~7;
}
/*
* Allocate buffer.
*/
if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
IP6_INC_STATS(ip6_dst_idev(skb->dst),
IPSTATS_MIB_FRAGFAILS);
err = -ENOMEM;
goto fail;
}
/*
* Set up data on packet
*/
ip6_copy_metadata(frag, skb);
skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev));
skb_put(frag, len + hlen + sizeof(struct frag_hdr));
skb_reset_network_header(frag);
fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
frag->transport_header = (frag->network_header + hlen +
sizeof(struct frag_hdr));
/*
* Charge the memory for the fragment to any owner
* it might possess
*/
if (skb->sk)
skb_set_owner_w(frag, skb->sk);
/*
* Copy the packet header into the new buffer.
*/
skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
/*
* Build fragment header.
*/
fh->nexthdr = nexthdr;
fh->reserved = 0;
if (!frag_id) {
ipv6_select_ident(skb, fh);
frag_id = fh->identification;
} else
fh->identification = frag_id;
/*
* Copy a block of the IP datagram.
*/
if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len))
BUG();
left -= len;
fh->frag_off = htons(offset);
if (left > 0)
fh->frag_off |= htons(IP6_MF);
ipv6_hdr(frag)->payload_len = htons(frag->len -
sizeof(struct ipv6hdr));
ptr += len;
offset += len;
/*
* Put this fragment into the sending queue.
*/
err = output(frag);
if (err)
goto fail;
IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGCREATES);
}
IP6_INC_STATS(ip6_dst_idev(skb->dst),
IPSTATS_MIB_FRAGOKS);
kfree_skb(skb);
return err;
fail:
IP6_INC_STATS(ip6_dst_idev(skb->dst),
IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return err;
}
static inline int ip6_rt_check(struct rt6key *rt_key,
struct in6_addr *fl_addr,
struct in6_addr *addr_cache)
{
return ((rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
(addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)));
}
static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
struct dst_entry *dst,
struct flowi *fl)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct rt6_info *rt = (struct rt6_info *)dst;
if (!dst)
goto out;
/* Yes, checking route validity in not connected
* case is not very simple. Take into account,
* that we do not support routing by source, TOS,
* and MSG_DONTROUTE --ANK (980726)
*
* 1. ip6_rt_check(): If route was host route,
* check that cached destination is current.
* If it is network route, we still may
* check its validity using saved pointer
* to the last used address: daddr_cache.
* We do not want to save whole address now,
* (because main consumer of this service
* is tcp, which has not this problem),
* so that the last trick works only on connected
* sockets.
* 2. oif also should be the same.
*/
if (ip6_rt_check(&rt->rt6i_dst, &fl->fl6_dst, np->daddr_cache) ||
#ifdef CONFIG_IPV6_SUBTREES
ip6_rt_check(&rt->rt6i_src, &fl->fl6_src, np->saddr_cache) ||
#endif
(fl->oif && fl->oif != dst->dev->ifindex)) {
dst_release(dst);
dst = NULL;
}
out:
return dst;
}
static int ip6_dst_lookup_tail(struct sock *sk,
struct dst_entry **dst, struct flowi *fl)
{
int err;
if (*dst == NULL)
*dst = ip6_route_output(sk, fl);
if ((err = (*dst)->error))
goto out_err_release;
if (ipv6_addr_any(&fl->fl6_src)) {
err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src);
if (err)
goto out_err_release;
}
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
/*
* Here if the dst entry we've looked up
* has a neighbour entry that is in the INCOMPLETE
* state and the src address from the flow is
* marked as OPTIMISTIC, we release the found
* dst entry and replace it instead with the
* dst entry of the nexthop router
*/
if (!((*dst)->neighbour->nud_state & NUD_VALID)) {
struct inet6_ifaddr *ifp;
struct flowi fl_gw;
int redirect;
ifp = ipv6_get_ifaddr(&fl->fl6_src, (*dst)->dev, 1);
redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
if (ifp)
in6_ifa_put(ifp);
if (redirect) {
/*
* We need to get the dst entry for the
* default router instead
*/
dst_release(*dst);
memcpy(&fl_gw, fl, sizeof(struct flowi));
memset(&fl_gw.fl6_dst, 0, sizeof(struct in6_addr));
*dst = ip6_route_output(sk, &fl_gw);
if ((err = (*dst)->error))
goto out_err_release;
}
}
#endif
return 0;
out_err_release:
if (err == -ENETUNREACH)
IP6_INC_STATS_BH(NULL, IPSTATS_MIB_OUTNOROUTES);
dst_release(*dst);
*dst = NULL;
return err;
}
/**
* ip6_dst_lookup - perform route lookup on flow
* @sk: socket which provides route info
* @dst: pointer to dst_entry * for result
* @fl: flow to lookup
*
* This function performs a route lookup on the given flow.
*
* It returns zero on success, or a standard errno code on error.
*/
int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
{
*dst = NULL;
return ip6_dst_lookup_tail(sk, dst, fl);
}
EXPORT_SYMBOL_GPL(ip6_dst_lookup);
/**
* ip6_sk_dst_lookup - perform socket cached route lookup on flow
* @sk: socket which provides the dst cache and route info
* @dst: pointer to dst_entry * for result
* @fl: flow to lookup
*
* This function performs a route lookup on the given flow with the
* possibility of using the cached route in the socket if it is valid.
* It will take the socket dst lock when operating on the dst cache.
* As a result, this function can only be used in process context.
*
* It returns zero on success, or a standard errno code on error.
*/
int ip6_sk_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
{
*dst = NULL;
if (sk) {
*dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
*dst = ip6_sk_dst_check(sk, *dst, fl);
}
return ip6_dst_lookup_tail(sk, dst, fl);
}
EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup);
static inline int ip6_ufo_append_data(struct sock *sk,
int getfrag(void *from, char *to, int offset, int len,
int odd, struct sk_buff *skb),
void *from, int length, int hh_len, int fragheaderlen,
int transhdrlen, int mtu,unsigned int flags)
{
struct sk_buff *skb;
int err;
/* There is support for UDP large send offload by network
* device, so create one single skb packet containing complete
* udp datagram
*/
if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
skb = sock_alloc_send_skb(sk,
hh_len + fragheaderlen + transhdrlen + 20,
(flags & MSG_DONTWAIT), &err);
if (skb == NULL)
return -ENOMEM;
/* reserve space for Hardware header */
skb_reserve(skb, hh_len);
/* create space for UDP/IP header */
skb_put(skb,fragheaderlen + transhdrlen);
/* initialize network header pointer */
skb_reset_network_header(skb);
/* initialize protocol header pointer */
skb->transport_header = skb->network_header + fragheaderlen;
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum = 0;
sk->sk_sndmsg_off = 0;
}
err = skb_append_datato_frags(sk,skb, getfrag, from,
(length - transhdrlen));
if (!err) {
struct frag_hdr fhdr;
/* specify the length of each IP datagram fragment*/
skb_shinfo(skb)->gso_size = mtu - fragheaderlen -
sizeof(struct frag_hdr);
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
ipv6_select_ident(skb, &fhdr);
skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
__skb_queue_tail(&sk->sk_write_queue, skb);
return 0;
}
/* There is not enough support do UPD LSO,
* so follow normal path
*/
kfree_skb(skb);
return err;
}
int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
int offset, int len, int odd, struct sk_buff *skb),
void *from, int length, int transhdrlen,
int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl,
struct rt6_info *rt, unsigned int flags)
{
struct inet_sock *inet = inet_sk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
struct sk_buff *skb;
unsigned int maxfraglen, fragheaderlen;
int exthdrlen;
int hh_len;
int mtu;
int copy;
int err;
int offset = 0;
int csummode = CHECKSUM_NONE;
if (flags&MSG_PROBE)
return 0;
if (skb_queue_empty(&sk->sk_write_queue)) {
/*
* setup for corking
*/
if (opt) {
if (np->cork.opt == NULL) {
np->cork.opt = kmalloc(opt->tot_len,
sk->sk_allocation);
if (unlikely(np->cork.opt == NULL))
return -ENOBUFS;
} else if (np->cork.opt->tot_len < opt->tot_len) {
printk(KERN_DEBUG "ip6_append_data: invalid option length\n");
return -EINVAL;
}
memcpy(np->cork.opt, opt, opt->tot_len);
inet->cork.flags |= IPCORK_OPT;
/* need source address above miyazawa*/
}
dst_hold(&rt->u.dst);
np->cork.rt = rt;
inet->cork.fl = *fl;
np->cork.hop_limit = hlimit;
np->cork.tclass = tclass;
mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
rt->u.dst.dev->mtu : dst_mtu(rt->u.dst.path);
if (np->frag_size < mtu) {
if (np->frag_size)
mtu = np->frag_size;
}
inet->cork.fragsize = mtu;
if (dst_allfrag(rt->u.dst.path))
inet->cork.flags |= IPCORK_ALLFRAG;
inet->cork.length = 0;
sk->sk_sndmsg_page = NULL;
sk->sk_sndmsg_off = 0;
exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0) -
rt->nfheader_len;
length += exthdrlen;
transhdrlen += exthdrlen;
} else {
rt = np->cork.rt;
fl = &inet->cork.fl;
if (inet->cork.flags & IPCORK_OPT)
opt = np->cork.opt;
transhdrlen = 0;
exthdrlen = 0;
mtu = inet->cork.fragsize;
}
hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
fragheaderlen = sizeof(struct ipv6hdr) + rt->nfheader_len +
(opt ? opt->opt_nflen : 0);
maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen);
return -EMSGSIZE;
}
}
/*
* Let's try using as much space as possible.
* Use MTU if total length of the message fits into the MTU.
* Otherwise, we need to reserve fragment header and
* fragment alignment (= 8-15 octects, in total).
*
* Note that we may need to "move" the data from the tail of
* of the buffer to the new fragment when we split
* the message.
*
* FIXME: It may be fragmented into multiple chunks
* at once if non-fragmentable extension headers
* are too large.
* --yoshfuji
*/
inet->cork.length += length;
if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) &&
(rt->u.dst.dev->features & NETIF_F_UFO)) {
err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,
fragheaderlen, transhdrlen, mtu,
flags);
if (err)
goto error;
return 0;
}
if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
goto alloc_new_skb;
while (length > 0) {
/* Check if the remaining data fits into current packet. */
copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
if (copy < length)
copy = maxfraglen - skb->len;
if (copy <= 0) {
char *data;
unsigned int datalen;
unsigned int fraglen;
unsigned int fraggap;
unsigned int alloclen;
struct sk_buff *skb_prev;
alloc_new_skb:
skb_prev = skb;
/* There's no room in the current skb */
if (skb_prev)
fraggap = skb_prev->len - maxfraglen;
else
fraggap = 0;
/*
* If remaining data exceeds the mtu,
* we know we need more fragment(s).
*/
datalen = length + fraggap;
if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
datalen = maxfraglen - fragheaderlen;
fraglen = datalen + fragheaderlen;
if ((flags & MSG_MORE) &&
!(rt->u.dst.dev->features&NETIF_F_SG))
alloclen = mtu;
else
alloclen = datalen + fragheaderlen;
/*
* The last fragment gets additional space at tail.
* Note: we overallocate on fragments with MSG_MODE
* because we have no idea if we're the last one.
*/
if (datalen == length + fraggap)
alloclen += rt->u.dst.trailer_len;
/*
* We just reserve space for fragment header.
* Note: this may be overallocation if the message
* (without MSG_MORE) fits into the MTU.
*/
alloclen += sizeof(struct frag_hdr);
if (transhdrlen) {
skb = sock_alloc_send_skb(sk,
alloclen + hh_len,
(flags & MSG_DONTWAIT), &err);
} else {
skb = NULL;
if (atomic_read(&sk->sk_wmem_alloc) <=
2 * sk->sk_sndbuf)
skb = sock_wmalloc(sk,
alloclen + hh_len, 1,
sk->sk_allocation);
if (unlikely(skb == NULL))
err = -ENOBUFS;
}
if (skb == NULL)
goto error;
/*
* Fill in the control structures
*/
skb->ip_summed = csummode;
skb->csum = 0;
/* reserve for fragmentation */
skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
/*
* Find where to start putting bytes
*/
data = skb_put(skb, fraglen);
skb_set_network_header(skb, exthdrlen);
data += fragheaderlen;
skb->transport_header = (skb->network_header +
fragheaderlen);
if (fraggap) {
skb->csum = skb_copy_and_csum_bits(
skb_prev, maxfraglen,
data + transhdrlen, fraggap, 0);
skb_prev->csum = csum_sub(skb_prev->csum,
skb->csum);
data += fraggap;
pskb_trim_unique(skb_prev, maxfraglen);
}
copy = datalen - transhdrlen - fraggap;
if (copy < 0) {
err = -EINVAL;
kfree_skb(skb);
goto error;
} else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
err = -EFAULT;
kfree_skb(skb);
goto error;
}
offset += copy;
length -= datalen - fraggap;
transhdrlen = 0;
exthdrlen = 0;
csummode = CHECKSUM_NONE;
/*
* Put the packet on the pending queue
*/
__skb_queue_tail(&sk->sk_write_queue, skb);
continue;
}
if (copy > length)
copy = length;
if (!(rt->u.dst.dev->features&NETIF_F_SG)) {
unsigned int off;
off = skb->len;
if (getfrag(from, skb_put(skb, copy),
offset, copy, off, skb) < 0) {
__skb_trim(skb, off);
err = -EFAULT;
goto error;
}
} else {
int i = skb_shinfo(skb)->nr_frags;
skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
struct page *page = sk->sk_sndmsg_page;
int off = sk->sk_sndmsg_off;
unsigned int left;
if (page && (left = PAGE_SIZE - off) > 0) {
if (copy >= left)
copy = left;
if (page != frag->page) {
if (i == MAX_SKB_FRAGS) {
err = -EMSGSIZE;
goto error;
}
get_page(page);
skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
frag = &skb_shinfo(skb)->frags[i];
}
} else if(i < MAX_SKB_FRAGS) {
if (copy > PAGE_SIZE)
copy = PAGE_SIZE;
page = alloc_pages(sk->sk_allocation, 0);
if (page == NULL) {
err = -ENOMEM;
goto error;
}
sk->sk_sndmsg_page = page;
sk->sk_sndmsg_off = 0;
skb_fill_page_desc(skb, i, page, 0, 0);
frag = &skb_shinfo(skb)->frags[i];
} else {
err = -EMSGSIZE;
goto error;
}
if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
err = -EFAULT;
goto error;
}
sk->sk_sndmsg_off += copy;
frag->size += copy;
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
atomic_add(copy, &sk->sk_wmem_alloc);
}
offset += copy;
length -= copy;
}
return 0;
error:
inet->cork.length -= length;
IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
return err;
}
static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
{
inet->cork.flags &= ~IPCORK_OPT;
kfree(np->cork.opt);
np->cork.opt = NULL;
if (np->cork.rt) {
dst_release(&np->cork.rt->u.dst);
np->cork.rt = NULL;
inet->cork.flags &= ~IPCORK_ALLFRAG;
}
memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
}
int ip6_push_pending_frames(struct sock *sk)
{
struct sk_buff *skb, *tmp_skb;
struct sk_buff **tail_skb;
struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
struct inet_sock *inet = inet_sk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
struct ipv6hdr *hdr;
struct ipv6_txoptions *opt = np->cork.opt;
struct rt6_info *rt = np->cork.rt;
struct flowi *fl = &inet->cork.fl;
unsigned char proto = fl->proto;
int err = 0;
if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
goto out;
tail_skb = &(skb_shinfo(skb)->frag_list);
/* move skb->data to ip header from ext header */
if (skb->data < skb_network_header(skb))
__skb_pull(skb, skb_network_offset(skb));
while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
__skb_pull(tmp_skb, skb_network_header_len(skb));
*tail_skb = tmp_skb;
tail_skb = &(tmp_skb->next);
skb->len += tmp_skb->len;
skb->data_len += tmp_skb->len;
skb->truesize += tmp_skb->truesize;
__sock_put(tmp_skb->sk);
tmp_skb->destructor = NULL;
tmp_skb->sk = NULL;
}
ipv6_addr_copy(final_dst, &fl->fl6_dst);
__skb_pull(skb, skb_network_header_len(skb));
if (opt && opt->opt_flen)
ipv6_push_frag_opts(skb, opt, &proto);
if (opt && opt->opt_nflen)
ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
hdr = ipv6_hdr(skb);
*(__be32*)hdr = fl->fl6_flowlabel |
htonl(0x60000000 | ((int)np->cork.tclass << 20));
hdr->hop_limit = np->cork.hop_limit;
hdr->nexthdr = proto;
ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
ipv6_addr_copy(&hdr->daddr, final_dst);
skb->priority = sk->sk_priority;
skb->dst = dst_clone(&rt->u.dst);
IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS);
if (proto == IPPROTO_ICMPV6) {
struct inet6_dev *idev = ip6_dst_idev(skb->dst);
ICMP6MSGOUT_INC_STATS_BH(idev, icmp6_hdr(skb)->icmp6_type);
ICMP6_INC_STATS_BH(idev, ICMP6_MIB_OUTMSGS);
}
err = ip6_local_out(skb);
if (err) {
if (err > 0)
err = np->recverr ? net_xmit_errno(err) : 0;
if (err)
goto error;
}
out:
ip6_cork_release(inet, np);
return err;
error:
goto out;
}
void ip6_flush_pending_frames(struct sock *sk)
{
struct sk_buff *skb;
while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
if (skb->dst)
IP6_INC_STATS(ip6_dst_idev(skb->dst),
IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
}
ip6_cork_release(inet_sk(sk), inet6_sk(sk));
}
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