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linux-zen-desktop/net/ipv6/ip6_output.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IPv6 output functions
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* Based on linux/net/ipv4/ip_output.c
*
* 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/slab.h>
#include <linux/bpf-cgroup.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>
#include <linux/mroute6.h>
#include <net/l3mdev.h>
#include <net/lwtunnel.h>
#include <net/ip_tunnels.h>
static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct net_device *dev = dst->dev;
struct inet6_dev *idev = ip6_dst_idev(dst);
unsigned int hh_len = LL_RESERVED_SPACE(dev);
const struct in6_addr *daddr, *nexthop;
struct ipv6hdr *hdr;
struct neighbour *neigh;
int ret;
/* Be paranoid, rather than too clever. */
if (unlikely(hh_len > skb_headroom(skb)) && dev->header_ops) {
skb = skb_expand_head(skb, hh_len);
if (!skb) {
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
return -ENOMEM;
}
}
hdr = ipv6_hdr(skb);
daddr = &hdr->daddr;
if (ipv6_addr_is_multicast(daddr)) {
if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
((mroute6_is_socket(net, skb) &&
!(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
ipv6_chk_mcast_addr(dev, daddr, &hdr->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(NFPROTO_IPV6, NF_INET_POST_ROUTING,
net, sk, newskb, NULL, newskb->dev,
dev_loopback_xmit);
if (hdr->hop_limit == 0) {
IP6_INC_STATS(net, idev,
IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
return 0;
}
}
IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
if (IPV6_ADDR_MC_SCOPE(daddr) <= IPV6_ADDR_SCOPE_NODELOCAL &&
!(dev->flags & IFF_LOOPBACK)) {
kfree_skb(skb);
return 0;
}
}
if (lwtunnel_xmit_redirect(dst->lwtstate)) {
int res = lwtunnel_xmit(skb);
if (res < 0 || res == LWTUNNEL_XMIT_DONE)
return res;
}
rcu_read_lock_bh();
nexthop = rt6_nexthop((struct rt6_info *)dst, daddr);
neigh = __ipv6_neigh_lookup_noref(dev, nexthop);
if (unlikely(IS_ERR_OR_NULL(neigh))) {
if (unlikely(!neigh))
neigh = __neigh_create(&nd_tbl, nexthop, dev, false);
if (IS_ERR(neigh)) {
rcu_read_unlock_bh();
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES);
kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
return -EINVAL;
}
}
sock_confirm_neigh(skb, neigh);
ret = neigh_output(neigh, skb, false);
rcu_read_unlock_bh();
return ret;
}
static int
ip6_finish_output_gso_slowpath_drop(struct net *net, struct sock *sk,
struct sk_buff *skb, unsigned int mtu)
{
struct sk_buff *segs, *nskb;
netdev_features_t features;
int ret = 0;
/* Please see corresponding comment in ip_finish_output_gso
* describing the cases where GSO segment length exceeds the
* egress MTU.
*/
features = netif_skb_features(skb);
segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
if (IS_ERR_OR_NULL(segs)) {
kfree_skb(skb);
return -ENOMEM;
}
consume_skb(skb);
skb_list_walk_safe(segs, segs, nskb) {
int err;
skb_mark_not_on_list(segs);
err = ip6_fragment(net, sk, segs, ip6_finish_output2);
if (err && ret == 0)
ret = err;
}
return ret;
}
static int __ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
unsigned int mtu;
#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
/* Policy lookup after SNAT yielded a new policy */
if (skb_dst(skb)->xfrm) {
IP6CB(skb)->flags |= IP6SKB_REROUTED;
return dst_output(net, sk, skb);
}
#endif
mtu = ip6_skb_dst_mtu(skb);
if (skb_is_gso(skb) &&
!(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) &&
!skb_gso_validate_network_len(skb, mtu))
return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu);
if ((skb->len > mtu && !skb_is_gso(skb)) ||
dst_allfrag(skb_dst(skb)) ||
(IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
return ip6_fragment(net, sk, skb, ip6_finish_output2);
else
return ip6_finish_output2(net, sk, skb);
}
static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
int ret;
ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
switch (ret) {
case NET_XMIT_SUCCESS:
case NET_XMIT_CN:
return __ip6_finish_output(net, sk, skb) ? : ret;
default:
kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
return ret;
}
}
int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev;
struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
skb->protocol = htons(ETH_P_IPV6);
skb->dev = dev;
if (unlikely(idev->cnf.disable_ipv6)) {
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
return 0;
}
return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
net, sk, skb, indev, dev,
ip6_finish_output,
!(IP6CB(skb)->flags & IP6SKB_REROUTED));
}
EXPORT_SYMBOL(ip6_output);
bool ip6_autoflowlabel(struct net *net, const struct ipv6_pinfo *np)
{
if (!np->autoflowlabel_set)
return ip6_default_np_autolabel(net);
else
return np->autoflowlabel;
}
/*
* xmit an sk_buff (used by TCP, SCTP and DCCP)
* Note : socket lock is not held for SYNACK packets, but might be modified
* by calls to skb_set_owner_w() and ipv6_local_error(),
* which are using proper atomic operations or spinlocks.
*/
int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
__u32 mark, struct ipv6_txoptions *opt, int tclass, u32 priority)
{
struct net *net = sock_net(sk);
const struct ipv6_pinfo *np = inet6_sk(sk);
struct in6_addr *first_hop = &fl6->daddr;
struct dst_entry *dst = skb_dst(skb);
struct net_device *dev = dst->dev;
struct inet6_dev *idev = ip6_dst_idev(dst);
struct hop_jumbo_hdr *hop_jumbo;
int hoplen = sizeof(*hop_jumbo);
unsigned int head_room;
struct ipv6hdr *hdr;
u8 proto = fl6->flowi6_proto;
int seg_len = skb->len;
int hlimit = -1;
u32 mtu;
head_room = sizeof(struct ipv6hdr) + hoplen + LL_RESERVED_SPACE(dev);
if (opt)
head_room += opt->opt_nflen + opt->opt_flen;
if (unlikely(head_room > skb_headroom(skb))) {
skb = skb_expand_head(skb, head_room);
if (!skb) {
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
return -ENOBUFS;
}
}
if (opt) {
seg_len += opt->opt_nflen + opt->opt_flen;
if (opt->opt_flen)
ipv6_push_frag_opts(skb, opt, &proto);
if (opt->opt_nflen)
ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop,
&fl6->saddr);
}
if (unlikely(seg_len > IPV6_MAXPLEN)) {
hop_jumbo = skb_push(skb, hoplen);
hop_jumbo->nexthdr = proto;
hop_jumbo->hdrlen = 0;
hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
hop_jumbo->tlv_len = 4;
hop_jumbo->jumbo_payload_len = htonl(seg_len + hoplen);
proto = IPPROTO_HOPOPTS;
seg_len = 0;
IP6CB(skb)->flags |= IP6SKB_FAKEJUMBO;
}
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
hdr = ipv6_hdr(skb);
/*
* Fill in the IPv6 header
*/
if (np)
hlimit = np->hop_limit;
if (hlimit < 0)
hlimit = ip6_dst_hoplimit(dst);
ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
ip6_autoflowlabel(net, np), fl6));
hdr->payload_len = htons(seg_len);
hdr->nexthdr = proto;
hdr->hop_limit = hlimit;
hdr->saddr = fl6->saddr;
hdr->daddr = *first_hop;
skb->protocol = htons(ETH_P_IPV6);
skb->priority = priority;
skb->mark = mark;
mtu = dst_mtu(dst);
if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
/* if egress device is enslaved to an L3 master device pass the
* skb to its handler for processing
*/
skb = l3mdev_ip6_out((struct sock *)sk, skb);
if (unlikely(!skb))
return 0;
/* hooks should never assume socket lock is held.
* we promote our socket to non const
*/
return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
net, (struct sock *)sk, skb, NULL, dev,
dst_output);
}
skb->dev = dev;
/* ipv6_local_error() does not require socket lock,
* we promote our socket to non const
*/
ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
IP6_INC_STATS(net, idev, IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return -EMSGSIZE;
}
EXPORT_SYMBOL(ip6_xmit);
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)) {
struct ipv6_pinfo *np = inet6_sk(sk);
if (np && np->rtalert_isolate &&
!net_eq(sock_net(sk), dev_net(skb->dev))) {
continue;
}
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;
__be16 frag_off;
int offset;
if (ipv6_ext_hdr(nexthdr)) {
offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
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 net *net, struct sock *sk,
struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
__IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
__IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
#ifdef CONFIG_NET_SWITCHDEV
if (skb->offload_l3_fwd_mark) {
consume_skb(skb);
return 0;
}
#endif
skb_clear_tstamp(skb);
return dst_output(net, sk, skb);
}
static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
{
if (skb->len <= mtu)
return false;
/* ipv6 conntrack defrag sets max_frag_size + ignore_df */
if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
return true;
if (skb->ignore_df)
return false;
if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
return false;
return true;
}
int ip6_forward(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct ipv6hdr *hdr = ipv6_hdr(skb);
struct inet6_skb_parm *opt = IP6CB(skb);
struct net *net = dev_net(dst->dev);
struct inet6_dev *idev;
SKB_DR(reason);
u32 mtu;
idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
if (net->ipv6.devconf_all->forwarding == 0)
goto error;
if (skb->pkt_type != PACKET_HOST)
goto drop;
if (unlikely(skb->sk))
goto drop;
if (skb_warn_if_lro(skb))
goto drop;
if (!net->ipv6.devconf_all->disable_policy &&
(!idev || !idev->cnf.disable_policy) &&
!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
__IP6_INC_STATS(net, idev, 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 (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
return 0;
}
/*
* check and decrement ttl
*/
if (hdr->hop_limit <= 1) {
icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
return -ETIMEDOUT;
}
/* XXX: idev->cnf.proxy_ndp? */
if (net->ipv6.devconf_all->proxy_ndp &&
pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
int proxied = ip6_forward_proxy_check(skb);
if (proxied > 0) {
/* It's tempting to decrease the hop limit
* here by 1, as we do at the end of the
* function too.
*
* But that would be incorrect, as proxying is
* not forwarding. The ip6_input function
* will handle this packet locally, and it
* depends on the hop limit being unchanged.
*
* One example is the NDP hop limit, that
* always has to stay 255, but other would be
* similar checks around RA packets, where the
* user can even change the desired limit.
*/
return ip6_input(skb);
} else if (proxied < 0) {
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
goto drop;
}
}
if (!xfrm6_route_forward(skb)) {
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
SKB_DR_SET(reason, XFRM_POLICY);
goto drop;
}
dst = skb_dst(skb);
/* 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 (IP6CB(skb)->iif == dst->dev->ifindex &&
opt->srcrt == 0 && !skb_sec_path(skb)) {
struct in6_addr *target = NULL;
struct inet_peer *peer;
struct rt6_info *rt;
/*
* incoming and outgoing devices are the same
* send a redirect.
*/
rt = (struct rt6_info *) dst;
if (rt->rt6i_flags & RTF_GATEWAY)
target = &rt->rt6i_gateway;
else
target = &hdr->daddr;
peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1);
/* Limit redirects both by destination (here)
and by source (inside ndisc_send_redirect)
*/
if (inet_peer_xrlim_allow(peer, 1*HZ))
ndisc_send_redirect(skb, target);
if (peer)
inet_putpeer(peer);
} else {
int addrtype = ipv6_addr_type(&hdr->saddr);
/* This check is security critical. */
if (addrtype == IPV6_ADDR_ANY ||
addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
goto error;
if (addrtype & IPV6_ADDR_LINKLOCAL) {
icmpv6_send(skb, ICMPV6_DEST_UNREACH,
ICMPV6_NOT_NEIGHBOUR, 0);
goto error;
}
}
mtu = ip6_dst_mtu_maybe_forward(dst, true);
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
if (ip6_pkt_too_big(skb, mtu)) {
/* Again, force OUTPUT device used as source address */
skb->dev = dst->dev;
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS);
__IP6_INC_STATS(net, ip6_dst_idev(dst),
IPSTATS_MIB_FRAGFAILS);
kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);
return -EMSGSIZE;
}
if (skb_cow(skb, dst->dev->hard_header_len)) {
__IP6_INC_STATS(net, 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--;
return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
net, NULL, skb, skb->dev, dst->dev,
ip6_forward_finish);
error:
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
SKB_DR_SET(reason, IP_INADDRERRORS);
drop:
kfree_skb_reason(skb, reason);
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;
skb_dst_drop(to);
skb_dst_set(to, dst_clone(skb_dst(from)));
to->dev = from->dev;
to->mark = from->mark;
skb_copy_hash(to, from);
#ifdef CONFIG_NET_SCHED
to->tc_index = from->tc_index;
#endif
nf_copy(to, from);
skb_ext_copy(to, from);
skb_copy_secmark(to, from);
}
int ip6_fraglist_init(struct sk_buff *skb, unsigned int hlen, u8 *prevhdr,
u8 nexthdr, __be32 frag_id,
struct ip6_fraglist_iter *iter)
{
unsigned int first_len;
struct frag_hdr *fh;
/* BUILD HEADER */
*prevhdr = NEXTHDR_FRAGMENT;
iter->tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
if (!iter->tmp_hdr)
return -ENOMEM;
iter->frag = skb_shinfo(skb)->frag_list;
skb_frag_list_init(skb);
iter->offset = 0;
iter->hlen = hlen;
iter->frag_id = frag_id;
iter->nexthdr = nexthdr;
__skb_pull(skb, hlen);
fh = __skb_push(skb, sizeof(struct frag_hdr));
__skb_push(skb, hlen);
skb_reset_network_header(skb);
memcpy(skb_network_header(skb), iter->tmp_hdr, hlen);
fh->nexthdr = nexthdr;
fh->reserved = 0;
fh->frag_off = htons(IP6_MF);
fh->identification = frag_id;
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));
return 0;
}
EXPORT_SYMBOL(ip6_fraglist_init);
void ip6_fraglist_prepare(struct sk_buff *skb,
struct ip6_fraglist_iter *iter)
{
struct sk_buff *frag = iter->frag;
unsigned int hlen = iter->hlen;
struct frag_hdr *fh;
frag->ip_summed = CHECKSUM_NONE;
skb_reset_transport_header(frag);
fh = __skb_push(frag, sizeof(struct frag_hdr));
__skb_push(frag, hlen);
skb_reset_network_header(frag);
memcpy(skb_network_header(frag), iter->tmp_hdr, hlen);
iter->offset += skb->len - hlen - sizeof(struct frag_hdr);
fh->nexthdr = iter->nexthdr;
fh->reserved = 0;
fh->frag_off = htons(iter->offset);
if (frag->next)
fh->frag_off |= htons(IP6_MF);
fh->identification = iter->frag_id;
ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
ip6_copy_metadata(frag, skb);
}
EXPORT_SYMBOL(ip6_fraglist_prepare);
void ip6_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int mtu,
unsigned short needed_tailroom, int hdr_room, u8 *prevhdr,
u8 nexthdr, __be32 frag_id, struct ip6_frag_state *state)
{
state->prevhdr = prevhdr;
state->nexthdr = nexthdr;
state->frag_id = frag_id;
state->hlen = hlen;
state->mtu = mtu;
state->left = skb->len - hlen; /* Space per frame */
state->ptr = hlen; /* Where to start from */
state->hroom = hdr_room;
state->troom = needed_tailroom;
state->offset = 0;
}
EXPORT_SYMBOL(ip6_frag_init);
struct sk_buff *ip6_frag_next(struct sk_buff *skb, struct ip6_frag_state *state)
{
u8 *prevhdr = state->prevhdr, *fragnexthdr_offset;
struct sk_buff *frag;
struct frag_hdr *fh;
unsigned int len;
len = state->left;
/* IF: it doesn't fit, use 'mtu' - the data space left */
if (len > state->mtu)
len = state->mtu;
/* IF: we are not sending up to and including the packet end
then align the next start on an eight byte boundary */
if (len < state->left)
len &= ~7;
/* Allocate buffer */
frag = alloc_skb(len + state->hlen + sizeof(struct frag_hdr) +
state->hroom + state->troom, GFP_ATOMIC);
if (!frag)
return ERR_PTR(-ENOMEM);
/*
* Set up data on packet
*/
ip6_copy_metadata(frag, skb);
skb_reserve(frag, state->hroom);
skb_put(frag, len + state->hlen + sizeof(struct frag_hdr));
skb_reset_network_header(frag);
fh = (struct frag_hdr *)(skb_network_header(frag) + state->hlen);
frag->transport_header = (frag->network_header + state->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), state->hlen);
fragnexthdr_offset = skb_network_header(frag);
fragnexthdr_offset += prevhdr - skb_network_header(skb);
*fragnexthdr_offset = NEXTHDR_FRAGMENT;
/*
* Build fragment header.
*/
fh->nexthdr = state->nexthdr;
fh->reserved = 0;
fh->identification = state->frag_id;
/*
* Copy a block of the IP datagram.
*/
BUG_ON(skb_copy_bits(skb, state->ptr, skb_transport_header(frag),
len));
state->left -= len;
fh->frag_off = htons(state->offset);
if (state->left > 0)
fh->frag_off |= htons(IP6_MF);
ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
state->ptr += len;
state->offset += len;
return frag;
}
EXPORT_SYMBOL(ip6_frag_next);
int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
int (*output)(struct net *, struct sock *, struct sk_buff *))
{
struct sk_buff *frag;
struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
inet6_sk(skb->sk) : NULL;
bool mono_delivery_time = skb->mono_delivery_time;
struct ip6_frag_state state;
unsigned int mtu, hlen, nexthdr_offset;
ktime_t tstamp = skb->tstamp;
int hroom, err = 0;
__be32 frag_id;
u8 *prevhdr, nexthdr = 0;
err = ip6_find_1stfragopt(skb, &prevhdr);
if (err < 0)
goto fail;
hlen = err;
nexthdr = *prevhdr;
nexthdr_offset = prevhdr - skb_network_header(skb);
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.
*/
if (unlikely(!skb->ignore_df && skb->len > mtu))
goto fail_toobig;
if (IP6CB(skb)->frag_max_size) {
if (IP6CB(skb)->frag_max_size > mtu)
goto fail_toobig;
/* don't send fragments larger than what we received */
mtu = IP6CB(skb)->frag_max_size;
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
}
if (np && np->frag_size < mtu) {
if (np->frag_size)
mtu = np->frag_size;
}
if (mtu < hlen + sizeof(struct frag_hdr) + 8)
goto fail_toobig;
mtu -= hlen + sizeof(struct frag_hdr);
frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
&ipv6_hdr(skb)->saddr);
if (skb->ip_summed == CHECKSUM_PARTIAL &&
(err = skb_checksum_help(skb)))
goto fail;
prevhdr = skb_network_header(skb) + nexthdr_offset;
hroom = LL_RESERVED_SPACE(rt->dst.dev);
if (skb_has_frag_list(skb)) {
unsigned int first_len = skb_pagelen(skb);
struct ip6_fraglist_iter iter;
struct sk_buff *frag2;
if (first_len - hlen > mtu ||
((first_len - hlen) & 7) ||
skb_cloned(skb) ||
skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
goto slow_path;
skb_walk_frags(skb, frag) {
/* Correct geometry. */
if (frag->len > mtu ||
((frag->len & 7) && frag->next) ||
skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
goto slow_path_clean;
/* Partially cloned skb? */
if (skb_shared(frag))
goto slow_path_clean;
BUG_ON(frag->sk);
if (skb->sk) {
frag->sk = skb->sk;
frag->destructor = sock_wfree;
}
skb->truesize -= frag->truesize;
}
err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
&iter);
if (err < 0)
goto fail;
/* We prevent @rt from being freed. */
rcu_read_lock();
for (;;) {
/* Prepare header of the next frame,
* before previous one went down. */
if (iter.frag)
ip6_fraglist_prepare(skb, &iter);
skb_set_delivery_time(skb, tstamp, mono_delivery_time);
err = output(net, sk, skb);
if (!err)
IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
IPSTATS_MIB_FRAGCREATES);
if (err || !iter.frag)
break;
skb = ip6_fraglist_next(&iter);
}
kfree(iter.tmp_hdr);
if (err == 0) {
IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
IPSTATS_MIB_FRAGOKS);
rcu_read_unlock();
return 0;
}
kfree_skb_list(iter.frag);
IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
IPSTATS_MIB_FRAGFAILS);
rcu_read_unlock();
return err;
slow_path_clean:
skb_walk_frags(skb, frag2) {
if (frag2 == frag)
break;
frag2->sk = NULL;
frag2->destructor = NULL;
skb->truesize += frag2->truesize;
}
}
slow_path:
/*
* Fragment the datagram.
*/
ip6_frag_init(skb, hlen, mtu, rt->dst.dev->needed_tailroom,
LL_RESERVED_SPACE(rt->dst.dev), prevhdr, nexthdr, frag_id,
&state);
/*
* Keep copying data until we run out.
*/
while (state.left > 0) {
frag = ip6_frag_next(skb, &state);
if (IS_ERR(frag)) {
err = PTR_ERR(frag);
goto fail;
}
/*
* Put this fragment into the sending queue.
*/
skb_set_delivery_time(frag, tstamp, mono_delivery_time);
err = output(net, sk, frag);
if (err)
goto fail;
IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_FRAGCREATES);
}
IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_FRAGOKS);
consume_skb(skb);
return err;
fail_toobig:
if (skb->sk && dst_allfrag(skb_dst(skb)))
sk_gso_disable(skb->sk);
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
err = -EMSGSIZE;
fail:
IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return err;
}
static inline int ip6_rt_check(const struct rt6key *rt_key,
const struct in6_addr *fl_addr,
const struct in6_addr *addr_cache)
{
return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
(!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
}
static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
struct dst_entry *dst,
const struct flowi6 *fl6)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct rt6_info *rt;
if (!dst)
goto out;
if (dst->ops->family != AF_INET6) {
dst_release(dst);
return NULL;
}
rt = (struct rt6_info *)dst;
/* 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, &fl6->daddr, np->daddr_cache) ||
#ifdef CONFIG_IPV6_SUBTREES
ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
#endif
(fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
dst_release(dst);
dst = NULL;
}
out:
return dst;
}
static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
struct dst_entry **dst, struct flowi6 *fl6)
{
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
struct neighbour *n;
struct rt6_info *rt;
#endif
int err;
int flags = 0;
/* The correct way to handle this would be to do
* ip6_route_get_saddr, and then ip6_route_output; however,
* the route-specific preferred source forces the
* ip6_route_output call _before_ ip6_route_get_saddr.
*
* In source specific routing (no src=any default route),
* ip6_route_output will fail given src=any saddr, though, so
* that's why we try it again later.
*/
if (ipv6_addr_any(&fl6->saddr)) {
struct fib6_info *from;
struct rt6_info *rt;
*dst = ip6_route_output(net, sk, fl6);
rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
rcu_read_lock();
from = rt ? rcu_dereference(rt->from) : NULL;
err = ip6_route_get_saddr(net, from, &fl6->daddr,
sk ? inet6_sk(sk)->srcprefs : 0,
&fl6->saddr);
rcu_read_unlock();
if (err)
goto out_err_release;
/* If we had an erroneous initial result, pretend it
* never existed and let the SA-enabled version take
* over.
*/
if ((*dst)->error) {
dst_release(*dst);
*dst = NULL;
}
if (fl6->flowi6_oif)
flags |= RT6_LOOKUP_F_IFACE;
}
if (!*dst)
*dst = ip6_route_output_flags(net, sk, fl6, flags);
err = (*dst)->error;
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
*/
rt = (struct rt6_info *) *dst;
rcu_read_lock_bh();
n = __ipv6_neigh_lookup_noref(rt->dst.dev,
rt6_nexthop(rt, &fl6->daddr));
err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
rcu_read_unlock_bh();
if (err) {
struct inet6_ifaddr *ifp;
struct flowi6 fl_gw6;
int redirect;
ifp = ipv6_get_ifaddr(net, &fl6->saddr,
(*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_gw6, fl6, sizeof(struct flowi6));
memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
*dst = ip6_route_output(net, sk, &fl_gw6);
err = (*dst)->error;
if (err)
goto out_err_release;
}
}
#endif
if (ipv6_addr_v4mapped(&fl6->saddr) &&
!(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) {
err = -EAFNOSUPPORT;
goto out_err_release;
}
return 0;
out_err_release:
dst_release(*dst);
*dst = NULL;
if (err == -ENETUNREACH)
IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
return err;
}
/**
* ip6_dst_lookup - perform route lookup on flow
* @net: Network namespace to perform lookup in
* @sk: socket which provides route info
* @dst: pointer to dst_entry * for result
* @fl6: 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 net *net, struct sock *sk, struct dst_entry **dst,
struct flowi6 *fl6)
{
*dst = NULL;
return ip6_dst_lookup_tail(net, sk, dst, fl6);
}
EXPORT_SYMBOL_GPL(ip6_dst_lookup);
/**
* ip6_dst_lookup_flow - perform route lookup on flow with ipsec
* @net: Network namespace to perform lookup in
* @sk: socket which provides route info
* @fl6: flow to lookup
* @final_dst: final destination address for ipsec lookup
*
* This function performs a route lookup on the given flow.
*
* It returns a valid dst pointer on success, or a pointer encoded
* error code.
*/
struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6,
const struct in6_addr *final_dst)
{
struct dst_entry *dst = NULL;
int err;
err = ip6_dst_lookup_tail(net, sk, &dst, fl6);
if (err)
return ERR_PTR(err);
if (final_dst)
fl6->daddr = *final_dst;
return xfrm_lookup_route(net, dst, flowi6_to_flowi(fl6), sk, 0);
}
EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
/**
* ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
* @sk: socket which provides the dst cache and route info
* @fl6: flow to lookup
* @final_dst: final destination address for ipsec lookup
* @connected: whether @sk is connected or not
*
* 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.
*
* In addition, for a connected socket, cache the dst in the socket
* if the current cache is not valid.
*
* It returns a valid dst pointer on success, or a pointer encoded
* error code.
*/
struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
const struct in6_addr *final_dst,
bool connected)
{
struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
dst = ip6_sk_dst_check(sk, dst, fl6);
if (dst)
return dst;
dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_dst);
if (connected && !IS_ERR(dst))
ip6_sk_dst_store_flow(sk, dst_clone(dst), fl6);
return dst;
}
EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
/**
* ip6_dst_lookup_tunnel - perform route lookup on tunnel
* @skb: Packet for which lookup is done
* @dev: Tunnel device
* @net: Network namespace of tunnel device
* @sock: Socket which provides route info
* @saddr: Memory to store the src ip address
* @info: Tunnel information
* @protocol: IP protocol
* @use_cache: Flag to enable cache usage
* This function performs a route lookup on a tunnel
*
* It returns a valid dst pointer and stores src address to be used in
* tunnel in param saddr on success, else a pointer encoded error code.
*/
struct dst_entry *ip6_dst_lookup_tunnel(struct sk_buff *skb,
struct net_device *dev,
struct net *net,
struct socket *sock,
struct in6_addr *saddr,
const struct ip_tunnel_info *info,
u8 protocol,
bool use_cache)
{
struct dst_entry *dst = NULL;
#ifdef CONFIG_DST_CACHE
struct dst_cache *dst_cache;
#endif
struct flowi6 fl6;
__u8 prio;
#ifdef CONFIG_DST_CACHE
dst_cache = (struct dst_cache *)&info->dst_cache;
if (use_cache) {
dst = dst_cache_get_ip6(dst_cache, saddr);
if (dst)
return dst;
}
#endif
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_mark = skb->mark;
fl6.flowi6_proto = protocol;
fl6.daddr = info->key.u.ipv6.dst;
fl6.saddr = info->key.u.ipv6.src;
prio = info->key.tos;
fl6.flowlabel = ip6_make_flowinfo(prio, info->key.label);
dst = ipv6_stub->ipv6_dst_lookup_flow(net, sock->sk, &fl6,
NULL);
if (IS_ERR(dst)) {
netdev_dbg(dev, "no route to %pI6\n", &fl6.daddr);
return ERR_PTR(-ENETUNREACH);
}
if (dst->dev == dev) { /* is this necessary? */
netdev_dbg(dev, "circular route to %pI6\n", &fl6.daddr);
dst_release(dst);
return ERR_PTR(-ELOOP);
}
#ifdef CONFIG_DST_CACHE
if (use_cache)
dst_cache_set_ip6(dst_cache, dst, &fl6.saddr);
#endif
*saddr = fl6.saddr;
return dst;
}
EXPORT_SYMBOL_GPL(ip6_dst_lookup_tunnel);
static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
gfp_t gfp)
{
return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
}
static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
gfp_t gfp)
{
return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
}
static void ip6_append_data_mtu(unsigned int *mtu,
int *maxfraglen,
unsigned int fragheaderlen,
struct sk_buff *skb,
struct rt6_info *rt,
unsigned int orig_mtu)
{
if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
if (!skb) {
/* first fragment, reserve header_len */
*mtu = orig_mtu - rt->dst.header_len;
} else {
/*
* this fragment is not first, the headers
* space is regarded as data space.
*/
*mtu = orig_mtu;
}
*maxfraglen = ((*mtu - fragheaderlen) & ~7)
+ fragheaderlen - sizeof(struct frag_hdr);
}
}
static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
struct rt6_info *rt)
{
struct ipv6_pinfo *np = inet6_sk(sk);
unsigned int mtu;
struct ipv6_txoptions *nopt, *opt = ipc6->opt;
/* callers pass dst together with a reference, set it first so
* ip6_cork_release() can put it down even in case of an error.
*/
cork->base.dst = &rt->dst;
/*
* setup for corking
*/
if (opt) {
if (WARN_ON(v6_cork->opt))
return -EINVAL;
nopt = v6_cork->opt = kzalloc(sizeof(*opt), sk->sk_allocation);
if (unlikely(!nopt))
return -ENOBUFS;
nopt->tot_len = sizeof(*opt);
nopt->opt_flen = opt->opt_flen;
nopt->opt_nflen = opt->opt_nflen;
nopt->dst0opt = ip6_opt_dup(opt->dst0opt, sk->sk_allocation);
if (opt->dst0opt && !nopt->dst0opt)
return -ENOBUFS;
nopt->dst1opt = ip6_opt_dup(opt->dst1opt, sk->sk_allocation);
if (opt->dst1opt && !nopt->dst1opt)
return -ENOBUFS;
nopt->hopopt = ip6_opt_dup(opt->hopopt, sk->sk_allocation);
if (opt->hopopt && !nopt->hopopt)
return -ENOBUFS;
nopt->srcrt = ip6_rthdr_dup(opt->srcrt, sk->sk_allocation);
if (opt->srcrt && !nopt->srcrt)
return -ENOBUFS;
/* need source address above miyazawa*/
}
v6_cork->hop_limit = ipc6->hlimit;
v6_cork->tclass = ipc6->tclass;
if (rt->dst.flags & DST_XFRM_TUNNEL)
mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
else
mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst));
if (np->frag_size < mtu) {
if (np->frag_size)
mtu = np->frag_size;
}
cork->base.fragsize = mtu;
cork->base.gso_size = ipc6->gso_size;
cork->base.tx_flags = 0;
cork->base.mark = ipc6->sockc.mark;
sock_tx_timestamp(sk, ipc6->sockc.tsflags, &cork->base.tx_flags);
if (dst_allfrag(xfrm_dst_path(&rt->dst)))
cork->base.flags |= IPCORK_ALLFRAG;
cork->base.length = 0;
cork->base.transmit_time = ipc6->sockc.transmit_time;
return 0;
}
static int __ip6_append_data(struct sock *sk,
struct sk_buff_head *queue,
struct inet_cork_full *cork_full,
struct inet6_cork *v6_cork,
struct page_frag *pfrag,
int getfrag(void *from, char *to, int offset,
int len, int odd, struct sk_buff *skb),
void *from, size_t length, int transhdrlen,
unsigned int flags, struct ipcm6_cookie *ipc6)
{
struct sk_buff *skb, *skb_prev = NULL;
struct inet_cork *cork = &cork_full->base;
struct flowi6 *fl6 = &cork_full->fl.u.ip6;
unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
struct ubuf_info *uarg = NULL;
int exthdrlen = 0;
int dst_exthdrlen = 0;
int hh_len;
int copy;
int err;
int offset = 0;
bool zc = false;
u32 tskey = 0;
struct rt6_info *rt = (struct rt6_info *)cork->dst;
struct ipv6_txoptions *opt = v6_cork->opt;
int csummode = CHECKSUM_NONE;
unsigned int maxnonfragsize, headersize;
unsigned int wmem_alloc_delta = 0;
bool paged, extra_uref = false;
skb = skb_peek_tail(queue);
if (!skb) {
exthdrlen = opt ? opt->opt_flen : 0;
dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
}
paged = !!cork->gso_size;
mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
orig_mtu = mtu;
if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP &&
sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
tskey = atomic_inc_return(&sk->sk_tskey) - 1;
hh_len = LL_RESERVED_SPACE(rt->dst.dev);
fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
(opt ? opt->opt_nflen : 0);
headersize = sizeof(struct ipv6hdr) +
(opt ? opt->opt_flen + opt->opt_nflen : 0) +
(dst_allfrag(&rt->dst) ?
sizeof(struct frag_hdr) : 0) +
rt->rt6i_nfheader_len;
if (mtu <= fragheaderlen ||
((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr))
goto emsgsize;
maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
sizeof(struct frag_hdr);
/* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit
* the first fragment
*/
if (headersize + transhdrlen > mtu)
goto emsgsize;
if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
(sk->sk_protocol == IPPROTO_UDP ||
sk->sk_protocol == IPPROTO_ICMPV6 ||
sk->sk_protocol == IPPROTO_RAW)) {
ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
sizeof(struct ipv6hdr));
goto emsgsize;
}
if (ip6_sk_ignore_df(sk))
maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
else
maxnonfragsize = mtu;
if (cork->length + length > maxnonfragsize - headersize) {
emsgsize:
pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0);
ipv6_local_error(sk, EMSGSIZE, fl6, pmtu);
return -EMSGSIZE;
}
/* CHECKSUM_PARTIAL only with no extension headers and when
* we are not going to fragment
*/
if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
headersize == sizeof(struct ipv6hdr) &&
length <= mtu - headersize &&
(!(flags & MSG_MORE) || cork->gso_size) &&
rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
csummode = CHECKSUM_PARTIAL;
if ((flags & MSG_ZEROCOPY) && length) {
struct msghdr *msg = from;
if (getfrag == ip_generic_getfrag && msg->msg_ubuf) {
if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb))
return -EINVAL;
/* Leave uarg NULL if can't zerocopy, callers should
* be able to handle it.
*/
if ((rt->dst.dev->features & NETIF_F_SG) &&
csummode == CHECKSUM_PARTIAL) {
paged = true;
zc = true;
uarg = msg->msg_ubuf;
}
} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));
if (!uarg)
return -ENOBUFS;
extra_uref = !skb_zcopy(skb); /* only ref on new uarg */
if (rt->dst.dev->features & NETIF_F_SG &&
csummode == CHECKSUM_PARTIAL) {
paged = true;
zc = true;
} else {
uarg_to_msgzc(uarg)->zerocopy = 0;
skb_zcopy_set(skb, uarg, &extra_uref);
}
}
}
/*
* 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 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
*/
cork->length += length;
if (!skb)
goto alloc_new_skb;
while (length > 0) {
/* Check if the remaining data fits into current packet. */
copy = (cork->length <= mtu && !(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, alloc_extra;
unsigned int pagedlen;
alloc_new_skb:
/* There's no room in the current skb */
if (skb)
fraggap = skb->len - maxfraglen;
else
fraggap = 0;
/* update mtu and maxfraglen if necessary */
if (!skb || !skb_prev)
ip6_append_data_mtu(&mtu, &maxfraglen,
fragheaderlen, skb, rt,
orig_mtu);
skb_prev = skb;
/*
* If remaining data exceeds the mtu,
* we know we need more fragment(s).
*/
datalen = length + fraggap;
if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
fraglen = datalen + fragheaderlen;
pagedlen = 0;
alloc_extra = hh_len;
alloc_extra += dst_exthdrlen;
alloc_extra += rt->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.
*/
alloc_extra += sizeof(struct frag_hdr);
if ((flags & MSG_MORE) &&
!(rt->dst.dev->features&NETIF_F_SG))
alloclen = mtu;
else if (!paged &&
(fraglen + alloc_extra < SKB_MAX_ALLOC ||
!(rt->dst.dev->features & NETIF_F_SG)))
alloclen = fraglen;
else {
alloclen = fragheaderlen + transhdrlen;
pagedlen = datalen - transhdrlen;
}
alloclen += alloc_extra;
if (datalen != length + fraggap) {
/*
* this is not the last fragment, the trailer
* space is regarded as data space.
*/
datalen += rt->dst.trailer_len;
}
fraglen = datalen + fragheaderlen;
copy = datalen - transhdrlen - fraggap - pagedlen;
if (copy < 0) {
err = -EINVAL;
goto error;
}
if (transhdrlen) {
skb = sock_alloc_send_skb(sk, alloclen,
(flags & MSG_DONTWAIT), &err);
} else {
skb = NULL;
if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <=
2 * sk->sk_sndbuf)
skb = alloc_skb(alloclen,
sk->sk_allocation);
if (unlikely(!skb))
err = -ENOBUFS;
}
if (!skb)
goto error;
/*
* Fill in the control structures
*/
skb->protocol = htons(ETH_P_IPV6);
skb->ip_summed = csummode;
skb->csum = 0;
/* reserve for fragmentation and ipsec header */
skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
dst_exthdrlen);
/*
* Find where to start putting bytes
*/
data = skb_put(skb, fraglen - pagedlen);
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);
skb_prev->csum = csum_sub(skb_prev->csum,
skb->csum);
data += fraggap;
pskb_trim_unique(skb_prev, maxfraglen);
}
if (copy > 0 &&
getfrag(from, data + transhdrlen, offset,
copy, fraggap, skb) < 0) {
err = -EFAULT;
kfree_skb(skb);
goto error;
}
offset += copy;
length -= copy + transhdrlen;
transhdrlen = 0;
exthdrlen = 0;
dst_exthdrlen = 0;
/* Only the initial fragment is time stamped */
skb_shinfo(skb)->tx_flags = cork->tx_flags;
cork->tx_flags = 0;
skb_shinfo(skb)->tskey = tskey;
tskey = 0;
skb_zcopy_set(skb, uarg, &extra_uref);
if ((flags & MSG_CONFIRM) && !skb_prev)
skb_set_dst_pending_confirm(skb, 1);
/*
* Put the packet on the pending queue
*/
if (!skb->destructor) {
skb->destructor = sock_wfree;
skb->sk = sk;
wmem_alloc_delta += skb->truesize;
}
__skb_queue_tail(queue, skb);
continue;
}
if (copy > length)
copy = length;
if (!(rt->dst.dev->features&NETIF_F_SG) &&
skb_tailroom(skb) >= copy) {
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 if (!zc) {
int i = skb_shinfo(skb)->nr_frags;
err = -ENOMEM;
if (!sk_page_frag_refill(sk, pfrag))
goto error;
skb_zcopy_downgrade_managed(skb);
if (!skb_can_coalesce(skb, i, pfrag->page,
pfrag->offset)) {
err = -EMSGSIZE;
if (i == MAX_SKB_FRAGS)
goto error;
__skb_fill_page_desc(skb, i, pfrag->page,
pfrag->offset, 0);
skb_shinfo(skb)->nr_frags = ++i;
get_page(pfrag->page);
}
copy = min_t(int, copy, pfrag->size - pfrag->offset);
if (getfrag(from,
page_address(pfrag->page) + pfrag->offset,
offset, copy, skb->len, skb) < 0)
goto error_efault;
pfrag->offset += copy;
skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
wmem_alloc_delta += copy;
} else {
err = skb_zerocopy_iter_dgram(skb, from, copy);
if (err < 0)
goto error;
}
offset += copy;
length -= copy;
}
if (wmem_alloc_delta)
refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
return 0;
error_efault:
err = -EFAULT;
error:
net_zcopy_put_abort(uarg, extra_uref);
cork->length -= length;
IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
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, size_t length, int transhdrlen,
struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
struct rt6_info *rt, unsigned int flags)
{
struct inet_sock *inet = inet_sk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
int exthdrlen;
int err;
if (flags&MSG_PROBE)
return 0;
if (skb_queue_empty(&sk->sk_write_queue)) {
/*
* setup for corking
*/
dst_hold(&rt->dst);
err = ip6_setup_cork(sk, &inet->cork, &np->cork,
ipc6, rt);
if (err)
return err;
inet->cork.fl.u.ip6 = *fl6;
exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
length += exthdrlen;
transhdrlen += exthdrlen;
} else {
transhdrlen = 0;
}
return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork,
&np->cork, sk_page_frag(sk), getfrag,
from, length, transhdrlen, flags, ipc6);
}
EXPORT_SYMBOL_GPL(ip6_append_data);
static void ip6_cork_steal_dst(struct sk_buff *skb, struct inet_cork_full *cork)
{
struct dst_entry *dst = cork->base.dst;
cork->base.dst = NULL;
cork->base.flags &= ~IPCORK_ALLFRAG;
skb_dst_set(skb, dst);
}
static void ip6_cork_release(struct inet_cork_full *cork,
struct inet6_cork *v6_cork)
{
if (v6_cork->opt) {
struct ipv6_txoptions *opt = v6_cork->opt;
kfree(opt->dst0opt);
kfree(opt->dst1opt);
kfree(opt->hopopt);
kfree(opt->srcrt);
kfree(opt);
v6_cork->opt = NULL;
}
if (cork->base.dst) {
dst_release(cork->base.dst);
cork->base.dst = NULL;
cork->base.flags &= ~IPCORK_ALLFRAG;
}
}
struct sk_buff *__ip6_make_skb(struct sock *sk,
struct sk_buff_head *queue,
struct inet_cork_full *cork,
struct inet6_cork *v6_cork)
{
struct sk_buff *skb, *tmp_skb;
struct sk_buff **tail_skb;
struct in6_addr *final_dst;
struct ipv6_pinfo *np = inet6_sk(sk);
struct net *net = sock_net(sk);
struct ipv6hdr *hdr;
struct ipv6_txoptions *opt = v6_cork->opt;
struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
struct flowi6 *fl6 = &cork->fl.u.ip6;
unsigned char proto = fl6->flowi6_proto;
skb = __skb_dequeue(queue);
if (!skb)
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(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;
tmp_skb->destructor = NULL;
tmp_skb->sk = NULL;
}
/* Allow local fragmentation. */
skb->ignore_df = ip6_sk_ignore_df(sk);
__skb_pull(skb, skb_network_header_len(skb));
final_dst = &fl6->daddr;
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, &fl6->saddr);
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
hdr = ipv6_hdr(skb);
ip6_flow_hdr(hdr, v6_cork->tclass,
ip6_make_flowlabel(net, skb, fl6->flowlabel,
ip6_autoflowlabel(net, np), fl6));
hdr->hop_limit = v6_cork->hop_limit;
hdr->nexthdr = proto;
hdr->saddr = fl6->saddr;
hdr->daddr = *final_dst;
skb->priority = sk->sk_priority;
skb->mark = cork->base.mark;
skb->tstamp = cork->base.transmit_time;
ip6_cork_steal_dst(skb, cork);
IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
if (proto == IPPROTO_ICMPV6) {
struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
u8 icmp6_type;
if (sk->sk_socket->type == SOCK_RAW && !inet_sk(sk)->hdrincl)
icmp6_type = fl6->fl6_icmp_type;
else
icmp6_type = icmp6_hdr(skb)->icmp6_type;
ICMP6MSGOUT_INC_STATS(net, idev, icmp6_type);
ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
}
ip6_cork_release(cork, v6_cork);
out:
return skb;
}
int ip6_send_skb(struct sk_buff *skb)
{
struct net *net = sock_net(skb->sk);
struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
int err;
err = ip6_local_out(net, skb->sk, skb);
if (err) {
if (err > 0)
err = net_xmit_errno(err);
if (err)
IP6_INC_STATS(net, rt->rt6i_idev,
IPSTATS_MIB_OUTDISCARDS);
}
return err;
}
int ip6_push_pending_frames(struct sock *sk)
{
struct sk_buff *skb;
skb = ip6_finish_skb(sk);
if (!skb)
return 0;
return ip6_send_skb(skb);
}
EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
static void __ip6_flush_pending_frames(struct sock *sk,
struct sk_buff_head *queue,
struct inet_cork_full *cork,
struct inet6_cork *v6_cork)
{
struct sk_buff *skb;
while ((skb = __skb_dequeue_tail(queue)) != NULL) {
if (skb_dst(skb))
IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
}
ip6_cork_release(cork, v6_cork);
}
void ip6_flush_pending_frames(struct sock *sk)
{
__ip6_flush_pending_frames(sk, &sk->sk_write_queue,
&inet_sk(sk)->cork, &inet6_sk(sk)->cork);
}
EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
struct sk_buff *ip6_make_skb(struct sock *sk,
int getfrag(void *from, char *to, int offset,
int len, int odd, struct sk_buff *skb),
void *from, size_t length, int transhdrlen,
struct ipcm6_cookie *ipc6, struct rt6_info *rt,
unsigned int flags, struct inet_cork_full *cork)
{
struct inet6_cork v6_cork;
struct sk_buff_head queue;
int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
int err;
if (flags & MSG_PROBE) {
dst_release(&rt->dst);
return NULL;
}
__skb_queue_head_init(&queue);
cork->base.flags = 0;
cork->base.addr = 0;
cork->base.opt = NULL;
v6_cork.opt = NULL;
err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt);
if (err) {
ip6_cork_release(cork, &v6_cork);
return ERR_PTR(err);
}
if (ipc6->dontfrag < 0)
ipc6->dontfrag = inet6_sk(sk)->dontfrag;
err = __ip6_append_data(sk, &queue, cork, &v6_cork,
&current->task_frag, getfrag, from,
length + exthdrlen, transhdrlen + exthdrlen,
flags, ipc6);
if (err) {
__ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
return ERR_PTR(err);
}
return __ip6_make_skb(sk, &queue, cork, &v6_cork);
}
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