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1729 lines
43 KiB
1729 lines
43 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* INET An implementation of the TCP/IP protocol suite for the LINUX |
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* operating system. INET is implemented using the BSD Socket |
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* interface as the means of communication with the user level. |
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* |
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* The Internet Protocol (IP) output module. |
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* |
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* Authors: Ross Biro |
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* Fred N. van Kempen, <[email protected]> |
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* Donald Becker, <[email protected]> |
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* Alan Cox, <[email protected]> |
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* Richard Underwood |
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* Stefan Becker, <[email protected]> |
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* Jorge Cwik, <[email protected]> |
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* Arnt Gulbrandsen, <[email protected]> |
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* Hirokazu Takahashi, <[email protected]> |
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* |
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* See ip_input.c for original log |
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* |
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* Fixes: |
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* Alan Cox : Missing nonblock feature in ip_build_xmit. |
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* Mike Kilburn : htons() missing in ip_build_xmit. |
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* Bradford Johnson: Fix faulty handling of some frames when |
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* no route is found. |
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* Alexander Demenshin: Missing sk/skb free in ip_queue_xmit |
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* (in case if packet not accepted by |
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* output firewall rules) |
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* Mike McLagan : Routing by source |
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* Alexey Kuznetsov: use new route cache |
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* Andi Kleen: Fix broken PMTU recovery and remove |
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* some redundant tests. |
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* Vitaly E. Lavrov : Transparent proxy revived after year coma. |
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* Andi Kleen : Replace ip_reply with ip_send_reply. |
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* Andi Kleen : Split fast and slow ip_build_xmit path |
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* for decreased register pressure on x86 |
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* and more readability. |
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* Marc Boucher : When call_out_firewall returns FW_QUEUE, |
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* silently drop skb instead of failing with -EPERM. |
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* Detlev Wengorz : Copy protocol for fragments. |
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* Hirokazu Takahashi: HW checksumming for outgoing UDP |
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* datagrams. |
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* Hirokazu Takahashi: sendfile() on UDP works now. |
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*/ |
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|
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#include <linux/uaccess.h> |
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#include <linux/module.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/mm.h> |
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#include <linux/string.h> |
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#include <linux/errno.h> |
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#include <linux/highmem.h> |
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#include <linux/slab.h> |
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|
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#include <linux/socket.h> |
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#include <linux/sockios.h> |
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#include <linux/in.h> |
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#include <linux/inet.h> |
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#include <linux/netdevice.h> |
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#include <linux/etherdevice.h> |
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#include <linux/proc_fs.h> |
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#include <linux/stat.h> |
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#include <linux/init.h> |
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|
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#include <net/snmp.h> |
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#include <net/ip.h> |
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#include <net/protocol.h> |
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#include <net/route.h> |
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#include <net/xfrm.h> |
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#include <linux/skbuff.h> |
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#include <net/sock.h> |
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#include <net/arp.h> |
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#include <net/icmp.h> |
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#include <net/checksum.h> |
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#include <net/inetpeer.h> |
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#include <net/inet_ecn.h> |
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#include <net/lwtunnel.h> |
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#include <linux/bpf-cgroup.h> |
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#include <linux/igmp.h> |
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#include <linux/netfilter_ipv4.h> |
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#include <linux/netfilter_bridge.h> |
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#include <linux/netlink.h> |
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#include <linux/tcp.h> |
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|
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static int |
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ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, |
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unsigned int mtu, |
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int (*output)(struct net *, struct sock *, struct sk_buff *)); |
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|
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/* Generate a checksum for an outgoing IP datagram. */ |
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void ip_send_check(struct iphdr *iph) |
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{ |
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iph->check = 0; |
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iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); |
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} |
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EXPORT_SYMBOL(ip_send_check); |
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|
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int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) |
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{ |
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struct iphdr *iph = ip_hdr(skb); |
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|
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iph->tot_len = htons(skb->len); |
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ip_send_check(iph); |
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|
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/* if egress device is enslaved to an L3 master device pass the |
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* skb to its handler for processing |
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*/ |
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skb = l3mdev_ip_out(sk, skb); |
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if (unlikely(!skb)) |
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return 0; |
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|
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skb->protocol = htons(ETH_P_IP); |
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|
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return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, |
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net, sk, skb, NULL, skb_dst(skb)->dev, |
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dst_output); |
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} |
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|
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int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) |
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{ |
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int err; |
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|
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err = __ip_local_out(net, sk, skb); |
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if (likely(err == 1)) |
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err = dst_output(net, sk, skb); |
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|
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return err; |
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} |
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EXPORT_SYMBOL_GPL(ip_local_out); |
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|
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static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst) |
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{ |
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int ttl = inet->uc_ttl; |
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|
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if (ttl < 0) |
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ttl = ip4_dst_hoplimit(dst); |
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return ttl; |
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} |
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|
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/* |
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* Add an ip header to a skbuff and send it out. |
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* |
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*/ |
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int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk, |
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__be32 saddr, __be32 daddr, struct ip_options_rcu *opt, |
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u8 tos) |
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{ |
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struct inet_sock *inet = inet_sk(sk); |
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struct rtable *rt = skb_rtable(skb); |
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struct net *net = sock_net(sk); |
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struct iphdr *iph; |
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|
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/* Build the IP header. */ |
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skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0)); |
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skb_reset_network_header(skb); |
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iph = ip_hdr(skb); |
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iph->version = 4; |
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iph->ihl = 5; |
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iph->tos = tos; |
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iph->ttl = ip_select_ttl(inet, &rt->dst); |
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iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr); |
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iph->saddr = saddr; |
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iph->protocol = sk->sk_protocol; |
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if (ip_dont_fragment(sk, &rt->dst)) { |
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iph->frag_off = htons(IP_DF); |
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iph->id = 0; |
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} else { |
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iph->frag_off = 0; |
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__ip_select_ident(net, iph, 1); |
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} |
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|
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if (opt && opt->opt.optlen) { |
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iph->ihl += opt->opt.optlen>>2; |
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ip_options_build(skb, &opt->opt, daddr, rt, 0); |
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} |
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|
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skb->priority = sk->sk_priority; |
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if (!skb->mark) |
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skb->mark = sk->sk_mark; |
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|
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/* Send it out. */ |
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return ip_local_out(net, skb->sk, skb); |
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} |
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EXPORT_SYMBOL_GPL(ip_build_and_send_pkt); |
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|
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static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) |
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{ |
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struct dst_entry *dst = skb_dst(skb); |
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struct rtable *rt = (struct rtable *)dst; |
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struct net_device *dev = dst->dev; |
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unsigned int hh_len = LL_RESERVED_SPACE(dev); |
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struct neighbour *neigh; |
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bool is_v6gw = false; |
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|
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if (rt->rt_type == RTN_MULTICAST) { |
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len); |
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} else if (rt->rt_type == RTN_BROADCAST) |
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len); |
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|
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if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { |
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skb = skb_expand_head(skb, hh_len); |
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if (!skb) |
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return -ENOMEM; |
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} |
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|
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if (lwtunnel_xmit_redirect(dst->lwtstate)) { |
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int res = lwtunnel_xmit(skb); |
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|
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if (res < 0 || res == LWTUNNEL_XMIT_DONE) |
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return res; |
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} |
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|
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rcu_read_lock_bh(); |
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neigh = ip_neigh_for_gw(rt, skb, &is_v6gw); |
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if (!IS_ERR(neigh)) { |
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int res; |
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|
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sock_confirm_neigh(skb, neigh); |
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/* if crossing protocols, can not use the cached header */ |
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res = neigh_output(neigh, skb, is_v6gw); |
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rcu_read_unlock_bh(); |
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return res; |
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} |
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rcu_read_unlock_bh(); |
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|
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net_dbg_ratelimited("%s: No header cache and no neighbour!\n", |
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__func__); |
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kfree_skb(skb); |
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return -EINVAL; |
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} |
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|
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static int ip_finish_output_gso(struct net *net, struct sock *sk, |
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struct sk_buff *skb, unsigned int mtu) |
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{ |
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struct sk_buff *segs, *nskb; |
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netdev_features_t features; |
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int ret = 0; |
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|
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/* common case: seglen is <= mtu |
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*/ |
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if (skb_gso_validate_network_len(skb, mtu)) |
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return ip_finish_output2(net, sk, skb); |
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|
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/* Slowpath - GSO segment length exceeds the egress MTU. |
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* |
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* This can happen in several cases: |
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* - Forwarding of a TCP GRO skb, when DF flag is not set. |
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* - Forwarding of an skb that arrived on a virtualization interface |
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* (virtio-net/vhost/tap) with TSO/GSO size set by other network |
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* stack. |
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* - Local GSO skb transmitted on an NETIF_F_TSO tunnel stacked over an |
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* interface with a smaller MTU. |
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* - Arriving GRO skb (or GSO skb in a virtualized environment) that is |
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* bridged to a NETIF_F_TSO tunnel stacked over an interface with an |
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* insufficient MTU. |
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*/ |
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features = netif_skb_features(skb); |
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BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET); |
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segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK); |
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if (IS_ERR_OR_NULL(segs)) { |
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kfree_skb(skb); |
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return -ENOMEM; |
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} |
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|
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consume_skb(skb); |
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|
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skb_list_walk_safe(segs, segs, nskb) { |
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int err; |
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|
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skb_mark_not_on_list(segs); |
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err = ip_fragment(net, sk, segs, mtu, ip_finish_output2); |
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|
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if (err && ret == 0) |
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ret = err; |
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} |
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|
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return ret; |
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} |
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|
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static int __ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
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{ |
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unsigned int mtu; |
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|
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#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM) |
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/* Policy lookup after SNAT yielded a new policy */ |
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if (skb_dst(skb)->xfrm) { |
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IPCB(skb)->flags |= IPSKB_REROUTED; |
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return dst_output(net, sk, skb); |
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} |
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#endif |
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mtu = ip_skb_dst_mtu(sk, skb); |
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if (skb_is_gso(skb)) |
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return ip_finish_output_gso(net, sk, skb, mtu); |
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|
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if (skb->len > mtu || IPCB(skb)->frag_max_size) |
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return ip_fragment(net, sk, skb, mtu, ip_finish_output2); |
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|
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return ip_finish_output2(net, sk, skb); |
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} |
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|
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static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
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{ |
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int ret; |
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|
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ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); |
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switch (ret) { |
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case NET_XMIT_SUCCESS: |
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return __ip_finish_output(net, sk, skb); |
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case NET_XMIT_CN: |
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return __ip_finish_output(net, sk, skb) ? : ret; |
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default: |
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kfree_skb(skb); |
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return ret; |
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} |
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} |
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|
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static int ip_mc_finish_output(struct net *net, struct sock *sk, |
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struct sk_buff *skb) |
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{ |
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struct rtable *new_rt; |
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bool do_cn = false; |
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int ret, err; |
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|
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ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb); |
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switch (ret) { |
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case NET_XMIT_CN: |
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do_cn = true; |
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fallthrough; |
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case NET_XMIT_SUCCESS: |
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break; |
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default: |
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kfree_skb(skb); |
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return ret; |
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} |
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|
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/* Reset rt_iif so that inet_iif() will return skb->skb_iif. Setting |
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* this to non-zero causes ipi_ifindex in in_pktinfo to be overwritten, |
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* see ipv4_pktinfo_prepare(). |
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*/ |
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new_rt = rt_dst_clone(net->loopback_dev, skb_rtable(skb)); |
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if (new_rt) { |
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new_rt->rt_iif = 0; |
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skb_dst_drop(skb); |
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skb_dst_set(skb, &new_rt->dst); |
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} |
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|
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err = dev_loopback_xmit(net, sk, skb); |
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return (do_cn && err) ? ret : err; |
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} |
|
|
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int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
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{ |
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struct rtable *rt = skb_rtable(skb); |
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struct net_device *dev = rt->dst.dev; |
|
|
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/* |
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* If the indicated interface is up and running, send the packet. |
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*/ |
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len); |
|
|
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skb->dev = dev; |
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skb->protocol = htons(ETH_P_IP); |
|
|
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/* |
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* Multicasts are looped back for other local users |
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*/ |
|
|
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if (rt->rt_flags&RTCF_MULTICAST) { |
|
if (sk_mc_loop(sk) |
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#ifdef CONFIG_IP_MROUTE |
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/* Small optimization: do not loopback not local frames, |
|
which returned after forwarding; they will be dropped |
|
by ip_mr_input in any case. |
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Note, that local frames are looped back to be delivered |
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to local recipients. |
|
|
|
This check is duplicated in ip_mr_input at the moment. |
|
*/ |
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&& |
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((rt->rt_flags & RTCF_LOCAL) || |
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!(IPCB(skb)->flags & IPSKB_FORWARDED)) |
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#endif |
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) { |
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struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); |
|
if (newskb) |
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NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
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net, sk, newskb, NULL, newskb->dev, |
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ip_mc_finish_output); |
|
} |
|
|
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/* Multicasts with ttl 0 must not go beyond the host */ |
|
|
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if (ip_hdr(skb)->ttl == 0) { |
|
kfree_skb(skb); |
|
return 0; |
|
} |
|
} |
|
|
|
if (rt->rt_flags&RTCF_BROADCAST) { |
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struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); |
|
if (newskb) |
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NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
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net, sk, newskb, NULL, newskb->dev, |
|
ip_mc_finish_output); |
|
} |
|
|
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return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, |
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net, sk, skb, NULL, skb->dev, |
|
ip_finish_output, |
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!(IPCB(skb)->flags & IPSKB_REROUTED)); |
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} |
|
|
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int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
|
{ |
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struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev; |
|
|
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len); |
|
|
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skb->dev = dev; |
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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)); |
|
} |
|
EXPORT_SYMBOL(ip_output); |
|
|
|
/* |
|
* 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)); |
|
|
|
iph->saddr = fl4->saddr; |
|
iph->daddr = 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); |
|
|
|
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) |
|
{ |
|
/* 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); |
|
|
|
if (iter.frag) |
|
ip_options_fragment(iter.frag); |
|
|
|
for (;;) { |
|
/* Prepare header of the next frame, |
|
* before previous one went down. */ |
|
if (iter.frag) { |
|
IPCB(iter.frag)->flags = IPCB(skb)->flags; |
|
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); |
|
|
|
/* |
|
* 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 = 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; |
|
} 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, alloc_extra; |
|
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; |
|
|
|
alloc_extra = hh_len + 15; |
|
alloc_extra += 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) |
|
alloc_extra += rt->dst.trailer_len; |
|
|
|
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 = min_t(int, fraglen, MAX_HEADER); |
|
pagedlen = fraglen - alloclen; |
|
} |
|
|
|
alloclen += alloc_extra; |
|
|
|
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->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: |
|
net_zcopy_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 |
|
}
|
|
|