diff options
Diffstat (limited to 'net/ipv6/ip6_output.c')
| -rw-r--r-- | net/ipv6/ip6_output.c | 2084 |
1 files changed, 2084 insertions, 0 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c new file mode 100644 index 000000000..e9ae084d0 --- /dev/null +++ b/net/ipv6/ip6_output.c @@ -0,0 +1,2084 @@ +// 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 != LWTUNNEL_XMIT_CONTINUE) + return res; + } + + rcu_read_lock(); + 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(); + 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(); + 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); + /* Last GSO segment can be smaller than gso_size (and MTU). + * Adding a fragment header would produce an "atomic fragment", + * which is considered harmful (RFC-8021). Avoid that. + */ + err = segs->len > mtu ? + ip6_fragment(net, sk, segs, ip6_finish_output2) : + ip6_finish_output2(net, sk, segs); + 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(); + n = __ipv6_neigh_lookup_noref(rt->dst.dev, + rt6_nexthop(rt, &fl6->daddr)); + err = n && !(READ_ONCE(n->nud_state) & NUD_VALID) ? -EINVAL : 0; + rcu_read_unlock(); + + 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_TSTAMP && + READ_ONCE(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, + ¤t->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); +} |