| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * INET An implementation of the TCP/IP protocol suite for the LINUX |
| * operating system. INET is implemented using the BSD Socket |
| * interface as the means of communication with the user level. |
| * |
| * The Internet Protocol (IP) output module. |
| * |
| * Authors: Ross Biro |
| * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
| * Donald Becker, <becker@super.org> |
| * Alan Cox, <Alan.Cox@linux.org> |
| * Richard Underwood |
| * Stefan Becker, <stefanb@yello.ping.de> |
| * Jorge Cwik, <jorge@laser.satlink.net> |
| * Arnt Gulbrandsen, <agulbra@nvg.unit.no> |
| * Hirokazu Takahashi, <taka@valinux.co.jp> |
| * |
| * See ip_input.c for original log |
| * |
| * Fixes: |
| * Alan Cox : Missing nonblock feature in ip_build_xmit. |
| * Mike Kilburn : htons() missing in ip_build_xmit. |
| * Bradford Johnson: Fix faulty handling of some frames when |
| * no route is found. |
| * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit |
| * (in case if packet not accepted by |
| * output firewall rules) |
| * Mike McLagan : Routing by source |
| * Alexey Kuznetsov: use new route cache |
| * Andi Kleen: Fix broken PMTU recovery and remove |
| * some redundant tests. |
| * Vitaly E. Lavrov : Transparent proxy revived after year coma. |
| * Andi Kleen : Replace ip_reply with ip_send_reply. |
| * Andi Kleen : Split fast and slow ip_build_xmit path |
| * for decreased register pressure on x86 |
| * and more readibility. |
| * Marc Boucher : When call_out_firewall returns FW_QUEUE, |
| * silently drop skb instead of failing with -EPERM. |
| * Detlev Wengorz : Copy protocol for fragments. |
| * Hirokazu Takahashi: HW checksumming for outgoing UDP |
| * datagrams. |
| * Hirokazu Takahashi: sendfile() on UDP works now. |
| */ |
| |
| #include <linux/uaccess.h> |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/string.h> |
| #include <linux/errno.h> |
| #include <linux/highmem.h> |
| #include <linux/slab.h> |
| |
| #include <linux/socket.h> |
| #include <linux/sockios.h> |
| #include <linux/in.h> |
| #include <linux/inet.h> |
| #include <linux/netdevice.h> |
| #include <linux/etherdevice.h> |
| #include <linux/proc_fs.h> |
| #include <linux/stat.h> |
| #include <linux/init.h> |
| |
| #include <net/snmp.h> |
| #include <net/ip.h> |
| #include <net/protocol.h> |
| #include <net/route.h> |
| #include <net/xfrm.h> |
| #include <linux/skbuff.h> |
| #include <net/sock.h> |
| #include <net/arp.h> |
| #include <net/icmp.h> |
| #include <net/checksum.h> |
| #include <net/inetpeer.h> |
| #include <net/inet_ecn.h> |
| #include <net/lwtunnel.h> |
| #include <linux/bpf-cgroup.h> |
| #include <linux/igmp.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <linux/netfilter_bridge.h> |
| #include <linux/netlink.h> |
| #include <linux/tcp.h> |
| |
| static int |
| ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, |
| unsigned int mtu, |
| int (*output)(struct net *, struct sock *, struct sk_buff *)); |
| |
| /* Generate a checksum for an outgoing IP datagram. */ |
| void ip_send_check(struct iphdr *iph) |
| { |
| iph->check = 0; |
| iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); |
| } |
| EXPORT_SYMBOL(ip_send_check); |
| |
| int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| struct iphdr *iph = ip_hdr(skb); |
| |
| iph->tot_len = htons(skb->len); |
| ip_send_check(iph); |
| |
| /* if egress device is enslaved to an L3 master device pass the |
| * skb to its handler for processing |
| */ |
| skb = l3mdev_ip_out(sk, skb); |
| if (unlikely(!skb)) |
| return 0; |
| |
| skb->protocol = htons(ETH_P_IP); |
| |
| return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, |
| net, sk, skb, NULL, skb_dst(skb)->dev, |
| dst_output); |
| } |
| |
| int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| int err; |
| |
| err = __ip_local_out(net, sk, skb); |
| if (likely(err == 1)) |
| err = dst_output(net, sk, skb); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(ip_local_out); |
| |
| static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) |
| { |
| int ttl = inet->uc_ttl; |
| |
| if (ttl < 0) |
| ttl = ip4_dst_hoplimit(dst); |
| return ttl; |
| } |
| |
| /* |
| * Add an ip header to a skbuff and send it out. |
| * |
| */ |
| int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk, |
| __be32 saddr, __be32 daddr, struct ip_options_rcu *opt, |
| u8 tos) |
| { |
| struct inet_sock *inet = inet_sk(sk); |
| struct rtable *rt = skb_rtable(skb); |
| struct net *net = sock_net(sk); |
| struct iphdr *iph; |
| |
| /* Build the IP header. */ |
| skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0)); |
| skb_reset_network_header(skb); |
| iph = ip_hdr(skb); |
| iph->version = 4; |
| iph->ihl = 5; |
| iph->tos = tos; |
| iph->ttl = ip_select_ttl(inet, &rt->dst); |
| iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr); |
| iph->saddr = saddr; |
| iph->protocol = sk->sk_protocol; |
| if (ip_dont_fragment(sk, &rt->dst)) { |
| iph->frag_off = htons(IP_DF); |
| iph->id = 0; |
| } else { |
| iph->frag_off = 0; |
| __ip_select_ident(net, iph, 1); |
| } |
| |
| if (opt && opt->opt.optlen) { |
| iph->ihl += opt->opt.optlen>>2; |
| ip_options_build(skb, &opt->opt, daddr, rt, 0); |
| } |
| |
| skb->priority = sk->sk_priority; |
| if (!skb->mark) |
| skb->mark = sk->sk_mark; |
| |
| /* Send it out. */ |
| return ip_local_out(net, skb->sk, skb); |
| } |
| EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); |
| |
| static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| struct dst_entry *dst = skb_dst(skb); |
| struct rtable *rt = (struct rtable *)dst; |
| struct net_device *dev = dst->dev; |
| unsigned int hh_len = LL_RESERVED_SPACE(dev); |
| struct neighbour *neigh; |
| bool is_v6gw = false; |
| |
| if (rt->rt_type == RTN_MULTICAST) { |
| IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len); |
| } else if (rt->rt_type == RTN_BROADCAST) |
| IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len); |
| |
| /* Be paranoid, rather than too clever. */ |
| if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { |
| struct sk_buff *skb2; |
| |
| skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); |
| if (!skb2) { |
| kfree_skb(skb); |
| return -ENOMEM; |
| } |
| if (skb->sk) |
| skb_set_owner_w(skb2, skb->sk); |
| consume_skb(skb); |
| skb = skb2; |
| } |
| |
| if (lwtunnel_xmit_redirect(dst->lwtstate)) { |
| int res = lwtunnel_xmit(skb); |
| |
| if (res < 0 || res == LWTUNNEL_XMIT_DONE) |
| return res; |
| } |
| |
| rcu_read_lock_bh(); |
| neigh = ip_neigh_for_gw(rt, skb, &is_v6gw); |
| if (!IS_ERR(neigh)) { |
| int res; |
| |
| sock_confirm_neigh(skb, neigh); |
| /* if crossing protocols, can not use the cached header */ |
| res = neigh_output(neigh, skb, is_v6gw); |
| rcu_read_unlock_bh(); |
| return res; |
| } |
| rcu_read_unlock_bh(); |
| |
| net_dbg_ratelimited("%s: No header cache and no neighbour!\n", |
| __func__); |
| kfree_skb(skb); |
| return -EINVAL; |
| } |
| |
| static int ip_finish_output_gso(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; |
| |
| /* common case: seglen is <= mtu |
| */ |
| if (skb_gso_validate_network_len(skb, mtu)) |
| return ip_finish_output2(net, sk, skb); |
| |
| /* Slowpath - GSO segment length exceeds the egress MTU. |
| * |
| * This can happen in several cases: |
| * - Forwarding of a TCP GRO skb, when DF flag is not set. |
| * - Forwarding of an skb that arrived on a virtualization interface |
| * (virtio-net/vhost/tap) with TSO/GSO size set by other network |
| * stack. |
| * - Local GSO skb transmitted on an NETIF_F_TSO tunnel stacked over an |
| * interface with a smaller MTU. |
| * - Arriving GRO skb (or GSO skb in a virtualized environment) that is |
| * bridged to a NETIF_F_TSO tunnel stacked over an interface with an |
| * insufficent MTU. |
| */ |
| features = netif_skb_features(skb); |
| BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET); |
| 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 = ip_fragment(net, sk, segs, mtu, ip_finish_output2); |
| |
| if (err && ret == 0) |
| ret = err; |
| } |
| |
| return ret; |
| } |
| |
| static int __ip_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) { |
| IPCB(skb)->flags |= IPSKB_REROUTED; |
| return dst_output(net, sk, skb); |
| } |
| #endif |
| mtu = ip_skb_dst_mtu(sk, skb); |
| if (skb_is_gso(skb)) |
| return ip_finish_output_gso(net, sk, skb, mtu); |
| |
| if (skb->len > mtu || IPCB(skb)->frag_max_size) |
| return ip_fragment(net, sk, skb, mtu, ip_finish_output2); |
| |
| return ip_finish_output2(net, sk, skb); |
| } |
| |
| static int ip_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: |
| return __ip_finish_output(net, sk, skb); |
| case NET_XMIT_CN: |
| return __ip_finish_output(net, sk, skb) ? : ret; |
| default: |
| kfree_skb(skb); |
| return ret; |
| } |
| } |
| |
| static int ip_mc_finish_output(struct net *net, struct sock *sk, |
| struct sk_buff *skb) |
| { |
| struct rtable *new_rt; |
| bool do_cn = false; |
| int ret, err; |
| |
| ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); |
| switch (ret) { |
| case NET_XMIT_CN: |
| do_cn = true; |
| fallthrough; |
| case NET_XMIT_SUCCESS: |
| break; |
| default: |
| kfree_skb(skb); |
| return ret; |
| } |
| |
| /* Reset rt_iif so that inet_iif() will return skb->skb_iif. Setting |
| * this to non-zero causes ipi_ifindex in in_pktinfo to be overwritten, |
| * see ipv4_pktinfo_prepare(). |
| */ |
| new_rt = rt_dst_clone(net->loopback_dev, skb_rtable(skb)); |
| if (new_rt) { |
| new_rt->rt_iif = 0; |
| skb_dst_drop(skb); |
| skb_dst_set(skb, &new_rt->dst); |
| } |
| |
| err = dev_loopback_xmit(net, sk, skb); |
| return (do_cn && err) ? ret : err; |
| } |
| |
| int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| struct rtable *rt = skb_rtable(skb); |
| struct net_device *dev = rt->dst.dev; |
| |
| /* |
| * If the indicated interface is up and running, send the packet. |
| */ |
| IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len); |
| |
| skb->dev = dev; |
| skb->protocol = htons(ETH_P_IP); |
| |
| /* |
| * Multicasts are looped back for other local users |
| */ |
| |
| if (rt->rt_flags&RTCF_MULTICAST) { |
| if (sk_mc_loop(sk) |
| #ifdef CONFIG_IP_MROUTE |
| /* Small optimization: do not loopback not local frames, |
| which returned after forwarding; they will be dropped |
| by ip_mr_input in any case. |
| Note, that local frames are looped back to be delivered |
| to local recipients. |
| |
| This check is duplicated in ip_mr_input at the moment. |
| */ |
| && |
| ((rt->rt_flags & RTCF_LOCAL) || |
| !(IPCB(skb)->flags & IPSKB_FORWARDED)) |
| #endif |
| ) { |
| struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); |
| if (newskb) |
| NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
| net, sk, newskb, NULL, newskb->dev, |
| ip_mc_finish_output); |
| } |
| |
| /* Multicasts with ttl 0 must not go beyond the host */ |
| |
| if (ip_hdr(skb)->ttl == 0) { |
| kfree_skb(skb); |
| return 0; |
| } |
| } |
| |
| if (rt->rt_flags&RTCF_BROADCAST) { |
| struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); |
| if (newskb) |
| NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
| net, sk, newskb, NULL, newskb->dev, |
| ip_mc_finish_output); |
| } |
| |
| return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
| net, sk, skb, NULL, skb->dev, |
| ip_finish_output, |
| !(IPCB(skb)->flags & IPSKB_REROUTED)); |
| } |
| |
| int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev; |
| |
| IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len); |
| |
| skb->dev = dev; |
| skb->protocol = htons(ETH_P_IP); |
| |
| return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
| net, sk, skb, indev, dev, |
| ip_finish_output, |
| !(IPCB(skb)->flags & IPSKB_REROUTED)); |
| } |
| |
| /* |
| * copy saddr and daddr, possibly using 64bit load/stores |
| * Equivalent to : |
| * iph->saddr = fl4->saddr; |
| * iph->daddr = fl4->daddr; |
| */ |
| static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4) |
| { |
| BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) != |
| offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr)); |
| memcpy(&iph->saddr, &fl4->saddr, |
| sizeof(fl4->saddr) + sizeof(fl4->daddr)); |
| } |
| |
| /* Note: skb->sk can be different from sk, in case of tunnels */ |
| int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, |
| __u8 tos) |
| { |
| struct inet_sock *inet = inet_sk(sk); |
| struct net *net = sock_net(sk); |
| struct ip_options_rcu *inet_opt; |
| struct flowi4 *fl4; |
| struct rtable *rt; |
| struct iphdr *iph; |
| int res; |
| |
| /* Skip all of this if the packet is already routed, |
| * f.e. by something like SCTP. |
| */ |
| rcu_read_lock(); |
| inet_opt = rcu_dereference(inet->inet_opt); |
| fl4 = &fl->u.ip4; |
| rt = skb_rtable(skb); |
| if (rt) |
| goto packet_routed; |
| |
| /* Make sure we can route this packet. */ |
| rt = (struct rtable *)__sk_dst_check(sk, 0); |
| if (!rt) { |
| __be32 daddr; |
| |
| /* Use correct destination address if we have options. */ |
| daddr = inet->inet_daddr; |
| if (inet_opt && inet_opt->opt.srr) |
| daddr = inet_opt->opt.faddr; |
| |
| /* If this fails, retransmit mechanism of transport layer will |
| * keep trying until route appears or the connection times |
| * itself out. |
| */ |
| rt = ip_route_output_ports(net, fl4, sk, |
| daddr, inet->inet_saddr, |
| inet->inet_dport, |
| inet->inet_sport, |
| sk->sk_protocol, |
| RT_CONN_FLAGS_TOS(sk, tos), |
| sk->sk_bound_dev_if); |
| if (IS_ERR(rt)) |
| goto no_route; |
| sk_setup_caps(sk, &rt->dst); |
| } |
| skb_dst_set_noref(skb, &rt->dst); |
| |
| packet_routed: |
| if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway) |
| goto no_route; |
| |
| /* OK, we know where to send it, allocate and build IP header. */ |
| skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0)); |
| skb_reset_network_header(skb); |
| iph = ip_hdr(skb); |
| *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (tos & 0xff)); |
| if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df) |
| iph->frag_off = htons(IP_DF); |
| else |
| iph->frag_off = 0; |
| iph->ttl = ip_select_ttl(inet, &rt->dst); |
| iph->protocol = sk->sk_protocol; |
| ip_copy_addrs(iph, fl4); |
| |
| /* Transport layer set skb->h.foo itself. */ |
| |
| if (inet_opt && inet_opt->opt.optlen) { |
| iph->ihl += inet_opt->opt.optlen >> 2; |
| ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0); |
| } |
| |
| ip_select_ident_segs(net, skb, sk, |
| skb_shinfo(skb)->gso_segs ?: 1); |
| |
| /* TODO : should we use skb->sk here instead of sk ? */ |
| skb->priority = sk->sk_priority; |
| skb->mark = sk->sk_mark; |
| |
| res = ip_local_out(net, sk, skb); |
| rcu_read_unlock(); |
| return res; |
| |
| no_route: |
| rcu_read_unlock(); |
| IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); |
| kfree_skb(skb); |
| return -EHOSTUNREACH; |
| } |
| EXPORT_SYMBOL(__ip_queue_xmit); |
| |
| int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl) |
| { |
| return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos); |
| } |
| EXPORT_SYMBOL(ip_queue_xmit); |
| |
| static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) |
| { |
| to->pkt_type = from->pkt_type; |
| to->priority = from->priority; |
| to->protocol = from->protocol; |
| to->skb_iif = from->skb_iif; |
| skb_dst_drop(to); |
| skb_dst_copy(to, 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); |
| #if IS_ENABLED(CONFIG_IP_VS) |
| to->ipvs_property = from->ipvs_property; |
| #endif |
| skb_copy_secmark(to, from); |
| } |
| |
| static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, |
| unsigned int mtu, |
| int (*output)(struct net *, struct sock *, struct sk_buff *)) |
| { |
| struct iphdr *iph = ip_hdr(skb); |
| |
| if ((iph->frag_off & htons(IP_DF)) == 0) |
| return ip_do_fragment(net, sk, skb, output); |
| |
| if (unlikely(!skb->ignore_df || |
| (IPCB(skb)->frag_max_size && |
| IPCB(skb)->frag_max_size > mtu))) { |
| IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); |
| icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, |
| htonl(mtu)); |
| kfree_skb(skb); |
| return -EMSGSIZE; |
| } |
| |
| return ip_do_fragment(net, sk, skb, output); |
| } |
| |
| void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph, |
| unsigned int hlen, struct ip_fraglist_iter *iter) |
| { |
| unsigned int first_len = skb_pagelen(skb); |
| |
| iter->frag = skb_shinfo(skb)->frag_list; |
| skb_frag_list_init(skb); |
| |
| iter->offset = 0; |
| iter->iph = iph; |
| iter->hlen = hlen; |
| |
| skb->data_len = first_len - skb_headlen(skb); |
| skb->len = first_len; |
| iph->tot_len = htons(first_len); |
| iph->frag_off = htons(IP_MF); |
| ip_send_check(iph); |
| } |
| EXPORT_SYMBOL(ip_fraglist_init); |
| |
| static void ip_fraglist_ipcb_prepare(struct sk_buff *skb, |
| struct ip_fraglist_iter *iter) |
| { |
| struct sk_buff *to = iter->frag; |
| |
| /* Copy the flags to each fragment. */ |
| IPCB(to)->flags = IPCB(skb)->flags; |
| |
| if (iter->offset == 0) |
| ip_options_fragment(to); |
| } |
| |
| void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter) |
| { |
| unsigned int hlen = iter->hlen; |
| struct iphdr *iph = iter->iph; |
| struct sk_buff *frag; |
| |
| frag = iter->frag; |
| frag->ip_summed = CHECKSUM_NONE; |
| skb_reset_transport_header(frag); |
| __skb_push(frag, hlen); |
| skb_reset_network_header(frag); |
| memcpy(skb_network_header(frag), iph, hlen); |
| iter->iph = ip_hdr(frag); |
| iph = iter->iph; |
| iph->tot_len = htons(frag->len); |
| ip_copy_metadata(frag, skb); |
| iter->offset += skb->len - hlen; |
| iph->frag_off = htons(iter->offset >> 3); |
| if (frag->next) |
| iph->frag_off |= htons(IP_MF); |
| /* Ready, complete checksum */ |
| ip_send_check(iph); |
| } |
| EXPORT_SYMBOL(ip_fraglist_prepare); |
| |
| void ip_frag_init(struct sk_buff *skb, unsigned int hlen, |
| unsigned int ll_rs, unsigned int mtu, bool DF, |
| struct ip_frag_state *state) |
| { |
| struct iphdr *iph = ip_hdr(skb); |
| |
| state->DF = DF; |
| state->hlen = hlen; |
| state->ll_rs = ll_rs; |
| state->mtu = mtu; |
| |
| state->left = skb->len - hlen; /* Space per frame */ |
| state->ptr = hlen; /* Where to start from */ |
| |
| state->offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; |
| state->not_last_frag = iph->frag_off & htons(IP_MF); |
| } |
| EXPORT_SYMBOL(ip_frag_init); |
| |
| static void ip_frag_ipcb(struct sk_buff *from, struct sk_buff *to, |
| bool first_frag, struct ip_frag_state *state) |
| { |
| /* Copy the flags to each fragment. */ |
| IPCB(to)->flags = IPCB(from)->flags; |
| |
| /* ANK: dirty, but effective trick. Upgrade options only if |
| * the segment to be fragmented was THE FIRST (otherwise, |
| * options are already fixed) and make it ONCE |
| * on the initial skb, so that all the following fragments |
| * will inherit fixed options. |
| */ |
| if (first_frag) |
| ip_options_fragment(from); |
| } |
| |
| struct sk_buff *ip_frag_next(struct sk_buff *skb, struct ip_frag_state *state) |
| { |
| unsigned int len = state->left; |
| struct sk_buff *skb2; |
| struct iphdr *iph; |
| |
| 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 */ |
| skb2 = alloc_skb(len + state->hlen + state->ll_rs, GFP_ATOMIC); |
| if (!skb2) |
| return ERR_PTR(-ENOMEM); |
| |
| /* |
| * Set up data on packet |
| */ |
| |
| ip_copy_metadata(skb2, skb); |
| skb_reserve(skb2, state->ll_rs); |
| skb_put(skb2, len + state->hlen); |
| skb_reset_network_header(skb2); |
| skb2->transport_header = skb2->network_header + state->hlen; |
| |
| /* |
| * Charge the memory for the fragment to any owner |
| * it might possess |
| */ |
| |
| if (skb->sk) |
| skb_set_owner_w(skb2, skb->sk); |
| |
| /* |
| * Copy the packet header into the new buffer. |
| */ |
| |
| skb_copy_from_linear_data(skb, skb_network_header(skb2), state->hlen); |
| |
| /* |
| * Copy a block of the IP datagram. |
| */ |
| if (skb_copy_bits(skb, state->ptr, skb_transport_header(skb2), len)) |
| BUG(); |
| state->left -= len; |
| |
| /* |
| * Fill in the new header fields. |
| */ |
| iph = ip_hdr(skb2); |
| iph->frag_off = htons((state->offset >> 3)); |
| if (state->DF) |
| iph->frag_off |= htons(IP_DF); |
| |
| /* |
| * Added AC : If we are fragmenting a fragment that's not the |
| * last fragment then keep MF on each bit |
| */ |
| if (state->left > 0 || state->not_last_frag) |
| iph->frag_off |= htons(IP_MF); |
| state->ptr += len; |
| state->offset += len; |
| |
| iph->tot_len = htons(len + state->hlen); |
| |
| ip_send_check(iph); |
| |
| return skb2; |
| } |
| EXPORT_SYMBOL(ip_frag_next); |
| |
| /* |
| * This IP datagram is too large to be sent in one piece. Break it up into |
| * smaller pieces (each of size equal to IP header plus |
| * a block of the data of the original IP data part) that will yet fit in a |
| * single device frame, and queue such a frame for sending. |
| */ |
| |
| int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, |
| int (*output)(struct net *, struct sock *, struct sk_buff *)) |
| { |
| struct iphdr *iph; |
| struct sk_buff *skb2; |
| struct rtable *rt = skb_rtable(skb); |
| unsigned int mtu, hlen, ll_rs; |
| struct ip_fraglist_iter iter; |
| ktime_t tstamp = skb->tstamp; |
| struct ip_frag_state state; |
| int err = 0; |
| |
| /* for offloaded checksums cleanup checksum before fragmentation */ |
| if (skb->ip_summed == CHECKSUM_PARTIAL && |
| (err = skb_checksum_help(skb))) |
| goto fail; |
| |
| /* |
| * Point into the IP datagram header. |
| */ |
| |
| iph = ip_hdr(skb); |
| |
| mtu = ip_skb_dst_mtu(sk, skb); |
| if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu) |
| mtu = IPCB(skb)->frag_max_size; |
| |
| /* |
| * Setup starting values. |
| */ |
| |
| hlen = iph->ihl * 4; |
| mtu = mtu - hlen; /* Size of data space */ |
| IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; |
| ll_rs = LL_RESERVED_SPACE(rt->dst.dev); |
| |
| /* When frag_list is given, use it. First, check its validity: |
| * some transformers could create wrong frag_list or break existing |
| * one, it is not prohibited. In this case fall back to copying. |
| * |
| * LATER: this step can be merged to real generation of fragments, |
| * we can switch to copy when see the first bad fragment. |
| */ |
| if (skb_has_frag_list(skb)) { |
| struct sk_buff *frag, *frag2; |
| unsigned int first_len = skb_pagelen(skb); |
| |
| if (first_len - hlen > mtu || |
| ((first_len - hlen) & 7) || |
| ip_is_fragment(iph) || |
| skb_cloned(skb) || |
| skb_headroom(skb) < ll_rs) |
| goto slow_path; |
| |
| skb_walk_frags(skb, frag) { |
| /* Correct geometry. */ |
| if (frag->len > mtu || |
| ((frag->len & 7) && frag->next) || |
| skb_headroom(frag) < hlen + ll_rs) |
| 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; |
| } |
| |
| /* Everything is OK. Generate! */ |
| ip_fraglist_init(skb, iph, hlen, &iter); |
| |
| for (;;) { |
| /* Prepare header of the next frame, |
| * before previous one went down. */ |
| if (iter.frag) { |
| ip_fraglist_ipcb_prepare(skb, &iter); |
| ip_fraglist_prepare(skb, &iter); |
| } |
| |
| skb->tstamp = tstamp; |
| err = output(net, sk, skb); |
| |
| if (!err) |
| IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES); |
| if (err || !iter.frag) |
| break; |
| |
| skb = ip_fraglist_next(&iter); |
| } |
| |
| if (err == 0) { |
| IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS); |
| return 0; |
| } |
| |
| kfree_skb_list(iter.frag); |
| |
| IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); |
| 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. |
| */ |
| |
| ip_frag_init(skb, hlen, ll_rs, mtu, IPCB(skb)->flags & IPSKB_FRAG_PMTU, |
| &state); |
| |
| /* |
| * Keep copying data until we run out. |
| */ |
| |
| while (state.left > 0) { |
| bool first_frag = (state.offset == 0); |
| |
| skb2 = ip_frag_next(skb, &state); |
| if (IS_ERR(skb2)) { |
| err = PTR_ERR(skb2); |
| goto fail; |
| } |
| ip_frag_ipcb(skb, skb2, first_frag, &state); |
| |
| /* |
| * Put this fragment into the sending queue. |
| */ |
| skb2->tstamp = tstamp; |
| err = output(net, sk, skb2); |
| if (err) |
| goto fail; |
| |
| IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES); |
| } |
| consume_skb(skb); |
| IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS); |
| return err; |
| |
| fail: |
| kfree_skb(skb); |
| IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS); |
| return err; |
| } |
| EXPORT_SYMBOL(ip_do_fragment); |
| |
| int |
| ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) |
| { |
| struct msghdr *msg = from; |
| |
| if (skb->ip_summed == CHECKSUM_PARTIAL) { |
| if (!copy_from_iter_full(to, len, &msg->msg_iter)) |
| return -EFAULT; |
| } else { |
| __wsum csum = 0; |
| if (!csum_and_copy_from_iter_full(to, len, &csum, &msg->msg_iter)) |
| return -EFAULT; |
| skb->csum = csum_block_add(skb->csum, csum, odd); |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(ip_generic_getfrag); |
| |
| static inline __wsum |
| csum_page(struct page *page, int offset, int copy) |
| { |
| char *kaddr; |
| __wsum csum; |
| kaddr = kmap(page); |
| csum = csum_partial(kaddr + offset, copy, 0); |
| kunmap(page); |
| return csum; |
| } |
| |
| static int __ip_append_data(struct sock *sk, |
| struct flowi4 *fl4, |
| struct sk_buff_head *queue, |
| struct inet_cork *cork, |
| struct page_frag *pfrag, |
| int getfrag(void *from, char *to, int offset, |
| int len, int odd, struct sk_buff *skb), |
| void *from, int length, int transhdrlen, |
| unsigned int flags) |
| { |
| struct inet_sock *inet = inet_sk(sk); |
| struct ubuf_info *uarg = NULL; |
| struct sk_buff *skb; |
| |
| struct ip_options *opt = cork->opt; |
| int hh_len; |
| int exthdrlen; |
| int mtu; |
| int copy; |
| int err; |
| int offset = 0; |
| unsigned int maxfraglen, fragheaderlen, maxnonfragsize; |
| int csummode = CHECKSUM_NONE; |
| struct rtable *rt = (struct rtable *)cork->dst; |
| unsigned int wmem_alloc_delta = 0; |
| bool paged, extra_uref = false; |
| u32 tskey = 0; |
| |
| skb = skb_peek_tail(queue); |
| |
| exthdrlen = !skb ? rt->dst.header_len : 0; |
| mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize; |
| paged = !!cork->gso_size; |
| |
| if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP && |
| sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) |
| tskey = sk->sk_tskey++; |
| |
| hh_len = LL_RESERVED_SPACE(rt->dst.dev); |
| |
| fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); |
| maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; |
| maxnonfragsize = ip_sk_ignore_df(sk) ? IP_MAX_MTU : mtu; |
| |
| if (cork->length + length > maxnonfragsize - fragheaderlen) { |
| ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, |
| mtu - (opt ? opt->optlen : 0)); |
| return -EMSGSIZE; |
| } |
| |
| /* |
| * transhdrlen > 0 means that this is the first fragment and we wish |
| * it won't be fragmented in the future. |
| */ |
| if (transhdrlen && |
| length + fragheaderlen <= mtu && |
| rt->dst.dev->features & (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM) && |
| (!(flags & MSG_MORE) || cork->gso_size) && |
| (!exthdrlen || (rt->dst.dev->features & NETIF_F_HW_ESP_TX_CSUM))) |
| csummode = CHECKSUM_PARTIAL; |
| |
| if (flags & MSG_ZEROCOPY && length && sock_flag(sk, SOCK_ZEROCOPY)) { |
| uarg = sock_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; |
| } else { |
| uarg->zerocopy = 0; |
| skb_zcopy_set(skb, uarg, &extra_uref); |
| } |
| } |
| |
| cork->length += length; |
| |
| /* So, what's going on in the loop below? |
| * |
| * We use calculated fragment length to generate chained skb, |
| * each of segments is IP fragment ready for sending to network after |
| * adding appropriate IP header. |
| */ |
| |
| if (!skb) |
| goto alloc_new_skb; |
| |
| while (length > 0) { |
| /* Check if the remaining data fits into current packet. */ |
| copy = mtu - 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; |
| unsigned int pagedlen; |
| struct sk_buff *skb_prev; |
| alloc_new_skb: |
| skb_prev = skb; |
| if (skb_prev) |
| fraggap = skb_prev->len - maxfraglen; |
| else |
| fraggap = 0; |
| |
| /* |
| * If remaining data exceeds the mtu, |
| * we know we need more fragment(s). |
| */ |
| datalen = length + fraggap; |
| if (datalen > mtu - fragheaderlen) |
| datalen = maxfraglen - fragheaderlen; |
| fraglen = datalen + fragheaderlen; |
| pagedlen = 0; |
| |
| if ((flags & MSG_MORE) && |
| !(rt->dst.dev->features&NETIF_F_SG)) |
| alloclen = mtu; |
| else if (!paged) |
| alloclen = fraglen; |
| else { |
| alloclen = min_t(int, fraglen, MAX_HEADER); |
| pagedlen = fraglen - alloclen; |
| } |
| |
| alloclen += exthdrlen; |
| |
| /* The last fragment gets additional space at tail. |
| * Note, with MSG_MORE we overallocate on fragments, |
| * because we have no idea what fragment will be |
| * the last. |
| */ |
| if (datalen == length + fraggap) |
| alloclen += rt->dst.trailer_len; |
| |
| if (transhdrlen) { |
| skb = sock_alloc_send_skb(sk, |
| alloclen + hh_len + 15, |
| (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 + hh_len + 15, |
| sk->sk_allocation); |
| if (unlikely(!skb)) |
| err = -ENOBUFS; |
| } |
| if (!skb) |
| goto error; |
| |
| /* |
| * Fill in the control structures |
| */ |
| skb->ip_summed = csummode; |
| skb->csum = 0; |
| skb_reserve(skb, hh_len); |
| |
| /* |
| * Find where to start putting bytes. |
| */ |
| data = skb_put(skb, fraglen + exthdrlen - pagedlen); |
| skb_set_network_header(skb, exthdrlen); |
| skb->transport_header = (skb->network_header + |
| fragheaderlen); |
| data += fragheaderlen + exthdrlen; |
| |
| 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); |
| } |
| |
| copy = datalen - transhdrlen - fraggap - pagedlen; |
| 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; |
| csummode = CHECKSUM_NONE; |
| |
| /* 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 (!uarg || !uarg->zerocopy) { |
| int i = skb_shinfo(skb)->nr_frags; |
| |
| err = -ENOMEM; |
| if (!sk_page_frag_refill(sk, pfrag)) |
| goto error; |
| |
| 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: |
| if (uarg) |
| sock_zerocopy_put_abort(uarg, extra_uref); |
| cork->length -= length; |
| IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); |
| refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc); |
| return err; |
| } |
| |
| static int ip_setup_cork(struct sock *sk, struct inet_cork *cork, |
| struct ipcm_cookie *ipc, struct rtable **rtp) |
| { |
| struct ip_options_rcu *opt; |
| struct rtable *rt; |
| |
| rt = *rtp; |
| if (unlikely(!rt)) |
| return -EFAULT; |
| |
| /* |
| * setup for corking. |
| */ |
| opt = ipc->opt; |
| if (opt) { |
| if (!cork->opt) { |
| cork->opt = kmalloc(sizeof(struct ip_options) + 40, |
| sk->sk_allocation); |
| if (unlikely(!cork->opt)) |
| return -ENOBUFS; |
| } |
| memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen); |
| cork->flags |= IPCORK_OPT; |
| cork->addr = ipc->addr; |
| } |
| |
| cork->fragsize = ip_sk_use_pmtu(sk) ? |
| dst_mtu(&rt->dst) : READ_ONCE(rt->dst.dev->mtu); |
| |
| if (!inetdev_valid_mtu(cork->fragsize)) |
| return -ENETUNREACH; |
| |
| cork->gso_size = ipc->gso_size; |
| |
| cork->dst = &rt->dst; |
| /* We stole this route, caller should not release it. */ |
| *rtp = NULL; |
| |
| cork->length = 0; |
| cork->ttl = ipc->ttl; |
| cork->tos = ipc->tos; |
| cork->mark = ipc->sockc.mark; |
| cork->priority = ipc->priority; |
| cork->transmit_time = ipc->sockc.transmit_time; |
| cork->tx_flags = 0; |
| sock_tx_timestamp(sk, ipc->sockc.tsflags, &cork->tx_flags); |
| |
| return 0; |
| } |
| |
| /* |
| * ip_append_data() and ip_append_page() can make one large IP datagram |
| * from many pieces of data. Each pieces will be holded on the socket |
| * until ip_push_pending_frames() is called. Each piece can be a page |
| * or non-page data. |
| * |
| * Not only UDP, other transport protocols - e.g. raw sockets - can use |
| * this interface potentially. |
| * |
| * LATER: length must be adjusted by pad at tail, when it is required. |
| */ |
| int ip_append_data(struct sock *sk, struct flowi4 *fl4, |
| int getfrag(void *from, char *to, int offset, int len, |
| int odd, struct sk_buff *skb), |
| void *from, int length, int transhdrlen, |
| struct ipcm_cookie *ipc, struct rtable **rtp, |
| unsigned int flags) |
| { |
| struct inet_sock *inet = inet_sk(sk); |
| int err; |
| |
| if (flags&MSG_PROBE) |
| return 0; |
| |
| if (skb_queue_empty(&sk->sk_write_queue)) { |
| err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp); |
| if (err) |
| return err; |
| } else { |
| transhdrlen = 0; |
| } |
| |
| return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base, |
| sk_page_frag(sk), getfrag, |
| from, length, transhdrlen, flags); |
| } |
| |
| ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, |
| int offset, size_t size, int flags) |
| { |
| struct inet_sock *inet = inet_sk(sk); |
| struct sk_buff *skb; |
| struct rtable *rt; |
| struct ip_options *opt = NULL; |
| struct inet_cork *cork; |
| int hh_len; |
| int mtu; |
| int len; |
| int err; |
| unsigned int maxfraglen, fragheaderlen, fraggap, maxnonfragsize; |
| |
| if (inet->hdrincl) |
| return -EPERM; |
| |
| if (flags&MSG_PROBE) |
| return 0; |
| |
| if (skb_queue_empty(&sk->sk_write_queue)) |
| return -EINVAL; |
| |
| cork = &inet->cork.base; |
| rt = (struct rtable *)cork->dst; |
| if (cork->flags & IPCORK_OPT) |
| opt = cork->opt; |
| |
| if (!(rt->dst.dev->features & NETIF_F_SG)) |
| return -EOPNOTSUPP; |
| |
| hh_len = LL_RESERVED_SPACE(rt->dst.dev); |
| mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize; |
| |
| fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0); |
| maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen; |
| maxnonfragsize = ip_sk_ignore_df(sk) ? 0xFFFF : mtu; |
| |
| if (cork->length + size > maxnonfragsize - fragheaderlen) { |
| ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport, |
| mtu - (opt ? opt->optlen : 0)); |
| return -EMSGSIZE; |
| } |
| |
| skb = skb_peek_tail(&sk->sk_write_queue); |
| if (!skb) |
| return -EINVAL; |
| |
| cork->length += size; |
| |
| while (size > 0) { |
| /* Check if the remaining data fits into current packet. */ |
| len = mtu - skb->len; |
| if (len < size) |
| len = maxfraglen - skb->len; |
| |
| if (len <= 0) { |
| struct sk_buff *skb_prev; |
| int alloclen; |
| |
| skb_prev = skb; |
| fraggap = skb_prev->len - maxfraglen; |
| |
| alloclen = fragheaderlen + hh_len + fraggap + 15; |
| skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation); |
| if (unlikely(!skb)) { |
| err = -ENOBUFS; |
| goto error; |
| } |
| |
| /* |
| * Fill in the control structures |
| */ |
| skb->ip_summed = CHECKSUM_NONE; |
| skb->csum = 0; |
| skb_reserve(skb, hh_len); |
| |
| /* |
| * Find where to start putting bytes. |
| */ |
| skb_put(skb, fragheaderlen + fraggap); |
| skb_reset_network_header(skb); |
| skb->transport_header = (skb->network_header + |
| fragheaderlen); |
| if (fraggap) { |
| skb->csum = skb_copy_and_csum_bits(skb_prev, |
| maxfraglen, |
| skb_transport_header(skb), |
| fraggap); |
| skb_prev->csum = csum_sub(skb_prev->csum, |
| skb->csum); |
| pskb_trim_unique(skb_prev, maxfraglen); |
| } |
| |
| /* |
| * Put the packet on the pending queue. |
| */ |
| __skb_queue_tail(&sk->sk_write_queue, skb); |
| continue; |
| } |
| |
| if (len > size) |
| len = size; |
| |
| if (skb_append_pagefrags(skb, page, offset, len)) { |
| err = -EMSGSIZE; |
| goto error; |
| } |
| |
| if (skb->ip_summed == CHECKSUM_NONE) { |
| __wsum csum; |
| csum = csum_page(page, offset, len); |
| skb->csum = csum_block_add(skb->csum, csum, skb->len); |
| } |
| |
| skb->len += len; |
| skb->data_len += len; |
| skb->truesize += len; |
| refcount_add(len, &sk->sk_wmem_alloc); |
| offset += len; |
| size -= len; |
| } |
| return 0; |
| |
| error: |
| cork->length -= size; |
| IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS); |
| return err; |
| } |
| |
| static void ip_cork_release(struct inet_cork *cork) |
| { |
| cork->flags &= ~IPCORK_OPT; |
| kfree(cork->opt); |
| cork->opt = NULL; |
| dst_release(cork->dst); |
| cork->dst = NULL; |
| } |
| |
| /* |
| * Combined all pending IP fragments on the socket as one IP datagram |
| * and push them out. |
| */ |
| struct sk_buff *__ip_make_skb(struct sock *sk, |
| struct flowi4 *fl4, |
| struct sk_buff_head *queue, |
| struct inet_cork *cork) |
| { |
| struct sk_buff *skb, *tmp_skb; |
| struct sk_buff **tail_skb; |
| struct inet_sock *inet = inet_sk(sk); |
| struct net *net = sock_net(sk); |
| struct ip_options *opt = NULL; |
| struct rtable *rt = (struct rtable *)cork->dst; |
| struct iphdr *iph; |
| __be16 df = 0; |
| __u8 ttl; |
| |
| 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; |
| } |
| |
| /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow |
| * to fragment the frame generated here. No matter, what transforms |
| * how transforms change size of the packet, it will come out. |
| */ |
| skb->ignore_df = ip_sk_ignore_df(sk); |
| |
| /* DF bit is set when we want to see DF on outgoing frames. |
| * If ignore_df is set too, we still allow to fragment this frame |
| * locally. */ |
| if (inet->pmtudisc == IP_PMTUDISC_DO || |
| inet->pmtudisc == IP_PMTUDISC_PROBE || |
| (skb->len <= dst_mtu(&rt->dst) && |
| ip_dont_fragment(sk, &rt->dst))) |
| df = htons(IP_DF); |
| |
| if (cork->flags & IPCORK_OPT) |
| opt = cork->opt; |
| |
| if (cork->ttl != 0) |
| ttl = cork->ttl; |
| else if (rt->rt_type == RTN_MULTICAST) |
| ttl = inet->mc_ttl; |
| else |
| ttl = ip_select_ttl(inet, &rt->dst); |
| |
| iph = ip_hdr(skb); |
| iph->version = 4; |
| iph->ihl = 5; |
| iph->tos = (cork->tos != -1) ? cork->tos : inet->tos; |
| iph->frag_off = df; |
| iph->ttl = ttl; |
| iph->protocol = sk->sk_protocol; |
| ip_copy_addrs(iph, fl4); |
| ip_select_ident(net, skb, sk); |
| |
| if (opt) { |
| iph->ihl += opt->optlen >> 2; |
| ip_options_build(skb, opt, cork->addr, rt, 0); |
| } |
| |
| skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority; |
| skb->mark = cork->mark; |
| skb->tstamp = cork->transmit_time; |
| /* |
| * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec |
| * on dst refcount |
| */ |
| cork->dst = NULL; |
| skb_dst_set(skb, &rt->dst); |
| |
| if (iph->protocol == IPPROTO_ICMP) |
| icmp_out_count(net, ((struct icmphdr *) |
| skb_transport_header(skb))->type); |
| |
| ip_cork_release(cork); |
| out: |
| return skb; |
| } |
| |
| int ip_send_skb(struct net *net, struct sk_buff *skb) |
| { |
| int err; |
| |
| err = ip_local_out(net, skb->sk, skb); |
| if (err) { |
| if (err > 0) |
| err = net_xmit_errno(err); |
| if (err) |
| IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); |
| } |
| |
| return err; |
| } |
| |
| int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4) |
| { |
| struct sk_buff *skb; |
| |
| skb = ip_finish_skb(sk, fl4); |
| if (!skb) |
| return 0; |
| |
| /* Netfilter gets whole the not fragmented skb. */ |
| return ip_send_skb(sock_net(sk), skb); |
| } |
| |
| /* |
| * Throw away all pending data on the socket. |
| */ |
| static void __ip_flush_pending_frames(struct sock *sk, |
| struct sk_buff_head *queue, |
| struct inet_cork *cork) |
| { |
| struct sk_buff *skb; |
| |
| while ((skb = __skb_dequeue_tail(queue)) != NULL) |
| kfree_skb(skb); |
| |
| ip_cork_release(cork); |
| } |
| |
| void ip_flush_pending_frames(struct sock *sk) |
| { |
| __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base); |
| } |
| |
| struct sk_buff *ip_make_skb(struct sock *sk, |
| struct flowi4 *fl4, |
| int getfrag(void *from, char *to, int offset, |
| int len, int odd, struct sk_buff *skb), |
| void *from, int length, int transhdrlen, |
| struct ipcm_cookie *ipc, struct rtable **rtp, |
| struct inet_cork *cork, unsigned int flags) |
| { |
| struct sk_buff_head queue; |
| int err; |
| |
| if (flags & MSG_PROBE) |
| return NULL; |
| |
| __skb_queue_head_init(&queue); |
| |
| cork->flags = 0; |
| cork->addr = 0; |
| cork->opt = NULL; |
| err = ip_setup_cork(sk, cork, ipc, rtp); |
| if (err) |
| return ERR_PTR(err); |
| |
| err = __ip_append_data(sk, fl4, &queue, cork, |
| ¤t->task_frag, getfrag, |
| from, length, transhdrlen, flags); |
| if (err) { |
| __ip_flush_pending_frames(sk, &queue, cork); |
| return ERR_PTR(err); |
| } |
| |
| return __ip_make_skb(sk, fl4, &queue, cork); |
| } |
| |
| /* |
| * Fetch data from kernel space and fill in checksum if needed. |
| */ |
| static int ip_reply_glue_bits(void *dptr, char *to, int offset, |
| int len, int odd, struct sk_buff *skb) |
| { |
| __wsum csum; |
| |
| csum = csum_partial_copy_nocheck(dptr+offset, to, len); |
| skb->csum = csum_block_add(skb->csum, csum, odd); |
| return 0; |
| } |
| |
| /* |
| * Generic function to send a packet as reply to another packet. |
| * Used to send some TCP resets/acks so far. |
| */ |
| void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, |
| const struct ip_options *sopt, |
| __be32 daddr, __be32 saddr, |
| const struct ip_reply_arg *arg, |
| unsigned int len, u64 transmit_time) |
| { |
| struct ip_options_data replyopts; |
| struct ipcm_cookie ipc; |
| struct flowi4 fl4; |
| struct rtable *rt = skb_rtable(skb); |
| struct net *net = sock_net(sk); |
| struct sk_buff *nskb; |
| int err; |
| int oif; |
| |
| if (__ip_options_echo(net, &replyopts.opt.opt, skb, sopt)) |
| return; |
| |
| ipcm_init(&ipc); |
| ipc.addr = daddr; |
| ipc.sockc.transmit_time = transmit_time; |
| |
| if (replyopts.opt.opt.optlen) { |
| ipc.opt = &replyopts.opt; |
| |
| if (replyopts.opt.opt.srr) |
| daddr = replyopts.opt.opt.faddr; |
| } |
| |
| oif = arg->bound_dev_if; |
| if (!oif && netif_index_is_l3_master(net, skb->skb_iif)) |
| oif = skb->skb_iif; |
| |
| flowi4_init_output(&fl4, oif, |
| IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark, |
| RT_TOS(arg->tos), |
| RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol, |
| ip_reply_arg_flowi_flags(arg), |
| daddr, saddr, |
| tcp_hdr(skb)->source, tcp_hdr(skb)->dest, |
| arg->uid); |
| security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4)); |
| rt = ip_route_output_key(net, &fl4); |
| if (IS_ERR(rt)) |
| return; |
| |
| inet_sk(sk)->tos = arg->tos & ~INET_ECN_MASK; |
| |
| sk->sk_protocol = ip_hdr(skb)->protocol; |
| sk->sk_bound_dev_if = arg->bound_dev_if; |
| sk->sk_sndbuf = sysctl_wmem_default; |
| ipc.sockc.mark = fl4.flowi4_mark; |
| err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, |
| len, 0, &ipc, &rt, MSG_DONTWAIT); |
| if (unlikely(err)) { |
| ip_flush_pending_frames(sk); |
| goto out; |
| } |
| |
| nskb = skb_peek(&sk->sk_write_queue); |
| if (nskb) { |
| if (arg->csumoffset >= 0) |
| *((__sum16 *)skb_transport_header(nskb) + |
| arg->csumoffset) = csum_fold(csum_add(nskb->csum, |
| arg->csum)); |
| nskb->ip_summed = CHECKSUM_NONE; |
| ip_push_pending_frames(sk, &fl4); |
| } |
| out: |
| ip_rt_put(rt); |
| } |
| |
| void __init ip_init(void) |
| { |
| ip_rt_init(); |
| inet_initpeers(); |
| |
| #if defined(CONFIG_IP_MULTICAST) |
| igmp_mc_init(); |
| #endif |
| } |