mirror of https://gitee.com/openkylin/linux.git
1451 lines
36 KiB
C
1451 lines
36 KiB
C
/*
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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, <waltje@uWalt.NL.Mugnet.ORG>
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* Donald Becker, <becker@super.org>
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* Alan Cox, <Alan.Cox@linux.org>
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* Richard Underwood
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* Stefan Becker, <stefanb@yello.ping.de>
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* Jorge Cwik, <jorge@laser.satlink.net>
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* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
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* Hirokazu Takahashi, <taka@valinux.co.jp>
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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 readibility.
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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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#include <asm/uaccess.h>
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#include <asm/system.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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#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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#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 <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/mroute.h>
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#include <linux/netlink.h>
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#include <linux/tcp.h>
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int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
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/* Generate a checksum for an outgoing IP datagram. */
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__inline__ 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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int __ip_local_out(struct sk_buff *skb)
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{
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struct iphdr *iph = ip_hdr(skb);
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iph->tot_len = htons(skb->len);
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ip_send_check(iph);
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return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, skb, NULL,
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skb_dst(skb)->dev, dst_output);
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}
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int ip_local_out(struct sk_buff *skb)
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{
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int err;
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err = __ip_local_out(skb);
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if (likely(err == 1))
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err = dst_output(skb);
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return err;
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}
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EXPORT_SYMBOL_GPL(ip_local_out);
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/* dev_loopback_xmit for use with netfilter. */
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static int ip_dev_loopback_xmit(struct sk_buff *newskb)
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{
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skb_reset_mac_header(newskb);
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__skb_pull(newskb, skb_network_offset(newskb));
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newskb->pkt_type = PACKET_LOOPBACK;
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newskb->ip_summed = CHECKSUM_UNNECESSARY;
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WARN_ON(!skb_dst(newskb));
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netif_rx_ni(newskb);
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return 0;
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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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if (ttl < 0)
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ttl = dst_metric(dst, RTAX_HOPLIMIT);
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return ttl;
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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, struct sock *sk,
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__be32 saddr, __be32 daddr, struct ip_options *opt)
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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 iphdr *iph;
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/* Build the IP header. */
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skb_push(skb, sizeof(struct iphdr) + (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 = inet->tos;
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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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else
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iph->frag_off = 0;
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iph->ttl = ip_select_ttl(inet, &rt->dst);
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iph->daddr = rt->rt_dst;
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iph->saddr = rt->rt_src;
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iph->protocol = sk->sk_protocol;
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ip_select_ident(iph, &rt->dst, sk);
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if (opt && opt->optlen) {
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iph->ihl += opt->optlen>>2;
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ip_options_build(skb, opt, daddr, rt, 0);
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}
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skb->priority = sk->sk_priority;
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skb->mark = sk->sk_mark;
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/* Send it out. */
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return ip_local_out(skb);
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}
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EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
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static inline int ip_finish_output2(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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if (rt->rt_type == RTN_MULTICAST) {
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IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len);
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} else if (rt->rt_type == RTN_BROADCAST)
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IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTBCAST, skb->len);
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/* Be paranoid, rather than too clever. */
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if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
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struct sk_buff *skb2;
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skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
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if (skb2 == NULL) {
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kfree_skb(skb);
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return -ENOMEM;
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}
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if (skb->sk)
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skb_set_owner_w(skb2, skb->sk);
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kfree_skb(skb);
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skb = skb2;
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}
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if (dst->hh)
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return neigh_hh_output(dst->hh, skb);
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else if (dst->neighbour)
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return dst->neighbour->output(skb);
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if (net_ratelimit())
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printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n");
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kfree_skb(skb);
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return -EINVAL;
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}
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static inline int ip_skb_dst_mtu(struct sk_buff *skb)
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{
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struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL;
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return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ?
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skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
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}
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static int ip_finish_output(struct sk_buff *skb)
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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 != NULL) {
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IPCB(skb)->flags |= IPSKB_REROUTED;
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return dst_output(skb);
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}
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#endif
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if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb))
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return ip_fragment(skb, ip_finish_output2);
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else
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return ip_finish_output2(skb);
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}
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int ip_mc_output(struct sk_buff *skb)
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{
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struct sock *sk = skb->sk;
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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(dev_net(dev), 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) {
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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,
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which returned after forwarding; they will be dropped
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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.
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This check is duplicated in ip_mr_input at the moment.
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*/
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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);
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if (newskb)
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NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
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newskb, NULL, newskb->dev,
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ip_dev_loopback_xmit);
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}
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/* Multicasts with ttl 0 must not go beyond the host */
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if (ip_hdr(skb)->ttl == 0) {
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kfree_skb(skb);
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return 0;
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}
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}
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if (rt->rt_flags&RTCF_BROADCAST) {
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struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
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if (newskb)
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NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, newskb,
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NULL, newskb->dev, ip_dev_loopback_xmit);
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}
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return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL,
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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 sk_buff *skb)
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{
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struct net_device *dev = skb_dst(skb)->dev;
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IP_UPD_PO_STATS(dev_net(dev), 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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return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, NULL, dev,
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ip_finish_output,
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!(IPCB(skb)->flags & IPSKB_REROUTED));
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}
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int ip_queue_xmit(struct sk_buff *skb)
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{
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struct sock *sk = skb->sk;
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struct inet_sock *inet = inet_sk(sk);
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struct ip_options *opt = inet->opt;
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struct rtable *rt;
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struct iphdr *iph;
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int res;
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/* Skip all of this if the packet is already routed,
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* f.e. by something like SCTP.
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*/
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rcu_read_lock();
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rt = skb_rtable(skb);
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if (rt != NULL)
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goto packet_routed;
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/* Make sure we can route this packet. */
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rt = (struct rtable *)__sk_dst_check(sk, 0);
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if (rt == NULL) {
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__be32 daddr;
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/* Use correct destination address if we have options. */
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daddr = inet->inet_daddr;
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if(opt && opt->srr)
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daddr = opt->faddr;
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{
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struct flowi fl = { .oif = sk->sk_bound_dev_if,
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.mark = sk->sk_mark,
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.nl_u = { .ip4_u =
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{ .daddr = daddr,
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.saddr = inet->inet_saddr,
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.tos = RT_CONN_FLAGS(sk) } },
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.proto = sk->sk_protocol,
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.flags = inet_sk_flowi_flags(sk),
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.uli_u = { .ports =
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{ .sport = inet->inet_sport,
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.dport = inet->inet_dport } } };
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/* If this fails, retransmit mechanism of transport layer will
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* keep trying until route appears or the connection times
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* itself out.
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*/
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security_sk_classify_flow(sk, &fl);
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if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0))
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goto no_route;
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}
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sk_setup_caps(sk, &rt->dst);
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}
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skb_dst_set_noref(skb, &rt->dst);
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packet_routed:
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if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
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goto no_route;
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/* OK, we know where to send it, allocate and build IP header. */
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skb_push(skb, sizeof(struct iphdr) + (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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*((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
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if (ip_dont_fragment(sk, &rt->dst) && !skb->local_df)
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iph->frag_off = htons(IP_DF);
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else
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iph->frag_off = 0;
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iph->ttl = ip_select_ttl(inet, &rt->dst);
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iph->protocol = sk->sk_protocol;
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iph->saddr = rt->rt_src;
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iph->daddr = rt->rt_dst;
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/* Transport layer set skb->h.foo itself. */
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if (opt && opt->optlen) {
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iph->ihl += opt->optlen >> 2;
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ip_options_build(skb, opt, inet->inet_daddr, rt, 0);
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}
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ip_select_ident_more(iph, &rt->dst, sk,
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(skb_shinfo(skb)->gso_segs ?: 1) - 1);
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skb->priority = sk->sk_priority;
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skb->mark = sk->sk_mark;
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|
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res = ip_local_out(skb);
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rcu_read_unlock();
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return res;
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no_route:
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rcu_read_unlock();
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IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
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kfree_skb(skb);
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return -EHOSTUNREACH;
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}
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EXPORT_SYMBOL(ip_queue_xmit);
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|
|
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static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
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{
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to->pkt_type = from->pkt_type;
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to->priority = from->priority;
|
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to->protocol = from->protocol;
|
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skb_dst_drop(to);
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skb_dst_copy(to, from);
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to->dev = from->dev;
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to->mark = from->mark;
|
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|
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/* Copy the flags to each fragment. */
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IPCB(to)->flags = IPCB(from)->flags;
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|
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#ifdef CONFIG_NET_SCHED
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to->tc_index = from->tc_index;
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#endif
|
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nf_copy(to, from);
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#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
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defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
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to->nf_trace = from->nf_trace;
|
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#endif
|
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#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
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to->ipvs_property = from->ipvs_property;
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#endif
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skb_copy_secmark(to, from);
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}
|
|
|
|
/*
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* This IP datagram is too large to be sent in one piece. Break it up into
|
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* smaller pieces (each of size equal to IP header plus
|
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* a block of the data of the original IP data part) that will yet fit in a
|
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* single device frame, and queue such a frame for sending.
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|
*/
|
|
|
|
int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
|
|
{
|
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struct iphdr *iph;
|
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int ptr;
|
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struct net_device *dev;
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struct sk_buff *skb2;
|
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unsigned int mtu, hlen, left, len, ll_rs, pad;
|
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int offset;
|
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__be16 not_last_frag;
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struct rtable *rt = skb_rtable(skb);
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int err = 0;
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|
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dev = rt->dst.dev;
|
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|
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/*
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* Point into the IP datagram header.
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*/
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|
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iph = ip_hdr(skb);
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|
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if (unlikely((iph->frag_off & htons(IP_DF)) && !skb->local_df)) {
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IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
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htonl(ip_skb_dst_mtu(skb)));
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kfree_skb(skb);
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return -EMSGSIZE;
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}
|
|
|
|
/*
|
|
* Setup starting values.
|
|
*/
|
|
|
|
hlen = iph->ihl * 4;
|
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mtu = dst_mtu(&rt->dst) - hlen; /* Size of data space */
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|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
if (skb->nf_bridge)
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mtu -= nf_bridge_mtu_reduction(skb);
|
|
#endif
|
|
IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
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|
|
|
/* 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_frags(skb)) {
|
|
struct sk_buff *frag;
|
|
int first_len = skb_pagelen(skb);
|
|
int truesizes = 0;
|
|
|
|
if (first_len - hlen > mtu ||
|
|
((first_len - hlen) & 7) ||
|
|
(iph->frag_off & htons(IP_MF|IP_OFFSET)) ||
|
|
skb_cloned(skb))
|
|
goto slow_path;
|
|
|
|
skb_walk_frags(skb, frag) {
|
|
/* Correct geometry. */
|
|
if (frag->len > mtu ||
|
|
((frag->len & 7) && frag->next) ||
|
|
skb_headroom(frag) < hlen)
|
|
goto slow_path;
|
|
|
|
/* Partially cloned skb? */
|
|
if (skb_shared(frag))
|
|
goto slow_path;
|
|
|
|
BUG_ON(frag->sk);
|
|
if (skb->sk) {
|
|
frag->sk = skb->sk;
|
|
frag->destructor = sock_wfree;
|
|
}
|
|
truesizes += frag->truesize;
|
|
}
|
|
|
|
/* Everything is OK. Generate! */
|
|
|
|
err = 0;
|
|
offset = 0;
|
|
frag = skb_shinfo(skb)->frag_list;
|
|
skb_frag_list_init(skb);
|
|
skb->data_len = first_len - skb_headlen(skb);
|
|
skb->truesize -= truesizes;
|
|
skb->len = first_len;
|
|
iph->tot_len = htons(first_len);
|
|
iph->frag_off = htons(IP_MF);
|
|
ip_send_check(iph);
|
|
|
|
for (;;) {
|
|
/* Prepare header of the next frame,
|
|
* before previous one went down. */
|
|
if (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);
|
|
iph = ip_hdr(frag);
|
|
iph->tot_len = htons(frag->len);
|
|
ip_copy_metadata(frag, skb);
|
|
if (offset == 0)
|
|
ip_options_fragment(frag);
|
|
offset += skb->len - hlen;
|
|
iph->frag_off = htons(offset>>3);
|
|
if (frag->next != NULL)
|
|
iph->frag_off |= htons(IP_MF);
|
|
/* Ready, complete checksum */
|
|
ip_send_check(iph);
|
|
}
|
|
|
|
err = output(skb);
|
|
|
|
if (!err)
|
|
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
|
|
if (err || !frag)
|
|
break;
|
|
|
|
skb = frag;
|
|
frag = skb->next;
|
|
skb->next = NULL;
|
|
}
|
|
|
|
if (err == 0) {
|
|
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
|
|
return 0;
|
|
}
|
|
|
|
while (frag) {
|
|
skb = frag->next;
|
|
kfree_skb(frag);
|
|
frag = skb;
|
|
}
|
|
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
|
|
return err;
|
|
}
|
|
|
|
slow_path:
|
|
left = skb->len - hlen; /* Space per frame */
|
|
ptr = hlen; /* Where to start from */
|
|
|
|
/* for bridged IP traffic encapsulated inside f.e. a vlan header,
|
|
* we need to make room for the encapsulating header
|
|
*/
|
|
pad = nf_bridge_pad(skb);
|
|
ll_rs = LL_RESERVED_SPACE_EXTRA(rt->dst.dev, pad);
|
|
mtu -= pad;
|
|
|
|
/*
|
|
* Fragment the datagram.
|
|
*/
|
|
|
|
offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
|
|
not_last_frag = iph->frag_off & htons(IP_MF);
|
|
|
|
/*
|
|
* Keep copying data until we run out.
|
|
*/
|
|
|
|
while (left > 0) {
|
|
len = left;
|
|
/* IF: it doesn't fit, use 'mtu' - the data space left */
|
|
if (len > mtu)
|
|
len = mtu;
|
|
/* IF: we are not sending upto and including the packet end
|
|
then align the next start on an eight byte boundary */
|
|
if (len < left) {
|
|
len &= ~7;
|
|
}
|
|
/*
|
|
* Allocate buffer.
|
|
*/
|
|
|
|
if ((skb2 = alloc_skb(len+hlen+ll_rs, GFP_ATOMIC)) == NULL) {
|
|
NETDEBUG(KERN_INFO "IP: frag: no memory for new fragment!\n");
|
|
err = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* Set up data on packet
|
|
*/
|
|
|
|
ip_copy_metadata(skb2, skb);
|
|
skb_reserve(skb2, ll_rs);
|
|
skb_put(skb2, len + hlen);
|
|
skb_reset_network_header(skb2);
|
|
skb2->transport_header = skb2->network_header + 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), hlen);
|
|
|
|
/*
|
|
* Copy a block of the IP datagram.
|
|
*/
|
|
if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
|
|
BUG();
|
|
left -= len;
|
|
|
|
/*
|
|
* Fill in the new header fields.
|
|
*/
|
|
iph = ip_hdr(skb2);
|
|
iph->frag_off = htons((offset >> 3));
|
|
|
|
/* 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 (offset == 0)
|
|
ip_options_fragment(skb);
|
|
|
|
/*
|
|
* Added AC : If we are fragmenting a fragment that's not the
|
|
* last fragment then keep MF on each bit
|
|
*/
|
|
if (left > 0 || not_last_frag)
|
|
iph->frag_off |= htons(IP_MF);
|
|
ptr += len;
|
|
offset += len;
|
|
|
|
/*
|
|
* Put this fragment into the sending queue.
|
|
*/
|
|
iph->tot_len = htons(len + hlen);
|
|
|
|
ip_send_check(iph);
|
|
|
|
err = output(skb2);
|
|
if (err)
|
|
goto fail;
|
|
|
|
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGCREATES);
|
|
}
|
|
kfree_skb(skb);
|
|
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGOKS);
|
|
return err;
|
|
|
|
fail:
|
|
kfree_skb(skb);
|
|
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL(ip_fragment);
|
|
|
|
int
|
|
ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
|
|
{
|
|
struct iovec *iov = from;
|
|
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL) {
|
|
if (memcpy_fromiovecend(to, iov, offset, len) < 0)
|
|
return -EFAULT;
|
|
} else {
|
|
__wsum csum = 0;
|
|
if (csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0)
|
|
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 inline int ip_ufo_append_data(struct sock *sk,
|
|
int getfrag(void *from, char *to, int offset, int len,
|
|
int odd, struct sk_buff *skb),
|
|
void *from, int length, int hh_len, int fragheaderlen,
|
|
int transhdrlen, int mtu, unsigned int flags)
|
|
{
|
|
struct sk_buff *skb;
|
|
int err;
|
|
|
|
/* There is support for UDP fragmentation offload by network
|
|
* device, so create one single skb packet containing complete
|
|
* udp datagram
|
|
*/
|
|
if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
|
|
skb = sock_alloc_send_skb(sk,
|
|
hh_len + fragheaderlen + transhdrlen + 20,
|
|
(flags & MSG_DONTWAIT), &err);
|
|
|
|
if (skb == NULL)
|
|
return err;
|
|
|
|
/* reserve space for Hardware header */
|
|
skb_reserve(skb, hh_len);
|
|
|
|
/* create space for UDP/IP header */
|
|
skb_put(skb, fragheaderlen + transhdrlen);
|
|
|
|
/* initialize network header pointer */
|
|
skb_reset_network_header(skb);
|
|
|
|
/* initialize protocol header pointer */
|
|
skb->transport_header = skb->network_header + fragheaderlen;
|
|
|
|
skb->ip_summed = CHECKSUM_PARTIAL;
|
|
skb->csum = 0;
|
|
sk->sk_sndmsg_off = 0;
|
|
|
|
/* specify the length of each IP datagram fragment */
|
|
skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
|
|
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
|
|
__skb_queue_tail(&sk->sk_write_queue, skb);
|
|
}
|
|
|
|
return skb_append_datato_frags(sk, skb, getfrag, from,
|
|
(length - transhdrlen));
|
|
}
|
|
|
|
/*
|
|
* 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,
|
|
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);
|
|
struct sk_buff *skb;
|
|
|
|
struct ip_options *opt = NULL;
|
|
int hh_len;
|
|
int exthdrlen;
|
|
int mtu;
|
|
int copy;
|
|
int err;
|
|
int offset = 0;
|
|
unsigned int maxfraglen, fragheaderlen;
|
|
int csummode = CHECKSUM_NONE;
|
|
struct rtable *rt;
|
|
|
|
if (flags&MSG_PROBE)
|
|
return 0;
|
|
|
|
if (skb_queue_empty(&sk->sk_write_queue)) {
|
|
/*
|
|
* setup for corking.
|
|
*/
|
|
opt = ipc->opt;
|
|
if (opt) {
|
|
if (inet->cork.opt == NULL) {
|
|
inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation);
|
|
if (unlikely(inet->cork.opt == NULL))
|
|
return -ENOBUFS;
|
|
}
|
|
memcpy(inet->cork.opt, opt, sizeof(struct ip_options)+opt->optlen);
|
|
inet->cork.flags |= IPCORK_OPT;
|
|
inet->cork.addr = ipc->addr;
|
|
}
|
|
rt = *rtp;
|
|
if (unlikely(!rt))
|
|
return -EFAULT;
|
|
/*
|
|
* We steal reference to this route, caller should not release it
|
|
*/
|
|
*rtp = NULL;
|
|
inet->cork.fragsize = mtu = inet->pmtudisc == IP_PMTUDISC_PROBE ?
|
|
rt->dst.dev->mtu :
|
|
dst_mtu(rt->dst.path);
|
|
inet->cork.dst = &rt->dst;
|
|
inet->cork.length = 0;
|
|
sk->sk_sndmsg_page = NULL;
|
|
sk->sk_sndmsg_off = 0;
|
|
if ((exthdrlen = rt->dst.header_len) != 0) {
|
|
length += exthdrlen;
|
|
transhdrlen += exthdrlen;
|
|
}
|
|
} else {
|
|
rt = (struct rtable *)inet->cork.dst;
|
|
if (inet->cork.flags & IPCORK_OPT)
|
|
opt = inet->cork.opt;
|
|
|
|
transhdrlen = 0;
|
|
exthdrlen = 0;
|
|
mtu = inet->cork.fragsize;
|
|
}
|
|
hh_len = LL_RESERVED_SPACE(rt->dst.dev);
|
|
|
|
fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
|
|
maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
|
|
|
|
if (inet->cork.length + length > 0xFFFF - fragheaderlen) {
|
|
ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->inet_dport,
|
|
mtu-exthdrlen);
|
|
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_V4_CSUM &&
|
|
!exthdrlen)
|
|
csummode = CHECKSUM_PARTIAL;
|
|
|
|
skb = skb_peek_tail(&sk->sk_write_queue);
|
|
|
|
inet->cork.length += length;
|
|
if (((length > mtu) || (skb && skb_is_gso(skb))) &&
|
|
(sk->sk_protocol == IPPROTO_UDP) &&
|
|
(rt->dst.dev->features & NETIF_F_UFO)) {
|
|
err = ip_ufo_append_data(sk, getfrag, from, length, hh_len,
|
|
fragheaderlen, transhdrlen, mtu,
|
|
flags);
|
|
if (err)
|
|
goto error;
|
|
return 0;
|
|
}
|
|
|
|
/* 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;
|
|
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;
|
|
|
|
if ((flags & MSG_MORE) &&
|
|
!(rt->dst.dev->features&NETIF_F_SG))
|
|
alloclen = mtu;
|
|
else
|
|
alloclen = datalen + fragheaderlen;
|
|
|
|
/* 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 (atomic_read(&sk->sk_wmem_alloc) <=
|
|
2 * sk->sk_sndbuf)
|
|
skb = sock_wmalloc(sk,
|
|
alloclen + hh_len + 15, 1,
|
|
sk->sk_allocation);
|
|
if (unlikely(skb == NULL))
|
|
err = -ENOBUFS;
|
|
else
|
|
/* only the initial fragment is
|
|
time stamped */
|
|
ipc->shtx.flags = 0;
|
|
}
|
|
if (skb == NULL)
|
|
goto error;
|
|
|
|
/*
|
|
* Fill in the control structures
|
|
*/
|
|
skb->ip_summed = csummode;
|
|
skb->csum = 0;
|
|
skb_reserve(skb, hh_len);
|
|
*skb_tx(skb) = ipc->shtx;
|
|
|
|
/*
|
|
* Find where to start putting bytes.
|
|
*/
|
|
data = skb_put(skb, fraglen);
|
|
skb_set_network_header(skb, exthdrlen);
|
|
skb->transport_header = (skb->network_header +
|
|
fragheaderlen);
|
|
data += fragheaderlen;
|
|
|
|
if (fraggap) {
|
|
skb->csum = skb_copy_and_csum_bits(
|
|
skb_prev, maxfraglen,
|
|
data + transhdrlen, fraggap, 0);
|
|
skb_prev->csum = csum_sub(skb_prev->csum,
|
|
skb->csum);
|
|
data += fraggap;
|
|
pskb_trim_unique(skb_prev, maxfraglen);
|
|
}
|
|
|
|
copy = datalen - transhdrlen - fraggap;
|
|
if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
|
|
err = -EFAULT;
|
|
kfree_skb(skb);
|
|
goto error;
|
|
}
|
|
|
|
offset += copy;
|
|
length -= datalen - fraggap;
|
|
transhdrlen = 0;
|
|
exthdrlen = 0;
|
|
csummode = CHECKSUM_NONE;
|
|
|
|
/*
|
|
* Put the packet on the pending queue.
|
|
*/
|
|
__skb_queue_tail(&sk->sk_write_queue, skb);
|
|
continue;
|
|
}
|
|
|
|
if (copy > length)
|
|
copy = length;
|
|
|
|
if (!(rt->dst.dev->features&NETIF_F_SG)) {
|
|
unsigned int off;
|
|
|
|
off = skb->len;
|
|
if (getfrag(from, skb_put(skb, copy),
|
|
offset, copy, off, skb) < 0) {
|
|
__skb_trim(skb, off);
|
|
err = -EFAULT;
|
|
goto error;
|
|
}
|
|
} else {
|
|
int i = skb_shinfo(skb)->nr_frags;
|
|
skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
|
|
struct page *page = sk->sk_sndmsg_page;
|
|
int off = sk->sk_sndmsg_off;
|
|
unsigned int left;
|
|
|
|
if (page && (left = PAGE_SIZE - off) > 0) {
|
|
if (copy >= left)
|
|
copy = left;
|
|
if (page != frag->page) {
|
|
if (i == MAX_SKB_FRAGS) {
|
|
err = -EMSGSIZE;
|
|
goto error;
|
|
}
|
|
get_page(page);
|
|
skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
|
|
frag = &skb_shinfo(skb)->frags[i];
|
|
}
|
|
} else if (i < MAX_SKB_FRAGS) {
|
|
if (copy > PAGE_SIZE)
|
|
copy = PAGE_SIZE;
|
|
page = alloc_pages(sk->sk_allocation, 0);
|
|
if (page == NULL) {
|
|
err = -ENOMEM;
|
|
goto error;
|
|
}
|
|
sk->sk_sndmsg_page = page;
|
|
sk->sk_sndmsg_off = 0;
|
|
|
|
skb_fill_page_desc(skb, i, page, 0, 0);
|
|
frag = &skb_shinfo(skb)->frags[i];
|
|
} else {
|
|
err = -EMSGSIZE;
|
|
goto error;
|
|
}
|
|
if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
|
|
err = -EFAULT;
|
|
goto error;
|
|
}
|
|
sk->sk_sndmsg_off += copy;
|
|
frag->size += copy;
|
|
skb->len += copy;
|
|
skb->data_len += copy;
|
|
skb->truesize += copy;
|
|
atomic_add(copy, &sk->sk_wmem_alloc);
|
|
}
|
|
offset += copy;
|
|
length -= copy;
|
|
}
|
|
|
|
return 0;
|
|
|
|
error:
|
|
inet->cork.length -= length;
|
|
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
|
|
return err;
|
|
}
|
|
|
|
ssize_t ip_append_page(struct sock *sk, 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;
|
|
int hh_len;
|
|
int mtu;
|
|
int len;
|
|
int err;
|
|
unsigned int maxfraglen, fragheaderlen, fraggap;
|
|
|
|
if (inet->hdrincl)
|
|
return -EPERM;
|
|
|
|
if (flags&MSG_PROBE)
|
|
return 0;
|
|
|
|
if (skb_queue_empty(&sk->sk_write_queue))
|
|
return -EINVAL;
|
|
|
|
rt = (struct rtable *)inet->cork.dst;
|
|
if (inet->cork.flags & IPCORK_OPT)
|
|
opt = inet->cork.opt;
|
|
|
|
if (!(rt->dst.dev->features&NETIF_F_SG))
|
|
return -EOPNOTSUPP;
|
|
|
|
hh_len = LL_RESERVED_SPACE(rt->dst.dev);
|
|
mtu = inet->cork.fragsize;
|
|
|
|
fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
|
|
maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
|
|
|
|
if (inet->cork.length + size > 0xFFFF - fragheaderlen) {
|
|
ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->inet_dport, mtu);
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
|
|
return -EINVAL;
|
|
|
|
inet->cork.length += size;
|
|
if ((size + skb->len > mtu) &&
|
|
(sk->sk_protocol == IPPROTO_UDP) &&
|
|
(rt->dst.dev->features & NETIF_F_UFO)) {
|
|
skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
|
|
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
|
|
}
|
|
|
|
|
|
while (size > 0) {
|
|
int i;
|
|
|
|
if (skb_is_gso(skb))
|
|
len = size;
|
|
else {
|
|
|
|
/* 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, 0);
|
|
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;
|
|
}
|
|
|
|
i = skb_shinfo(skb)->nr_frags;
|
|
if (len > size)
|
|
len = size;
|
|
if (skb_can_coalesce(skb, i, page, offset)) {
|
|
skb_shinfo(skb)->frags[i-1].size += len;
|
|
} else if (i < MAX_SKB_FRAGS) {
|
|
get_page(page);
|
|
skb_fill_page_desc(skb, i, page, offset, len);
|
|
} else {
|
|
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;
|
|
atomic_add(len, &sk->sk_wmem_alloc);
|
|
offset += len;
|
|
size -= len;
|
|
}
|
|
return 0;
|
|
|
|
error:
|
|
inet->cork.length -= size;
|
|
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
|
|
return err;
|
|
}
|
|
|
|
static void ip_cork_release(struct inet_sock *inet)
|
|
{
|
|
inet->cork.flags &= ~IPCORK_OPT;
|
|
kfree(inet->cork.opt);
|
|
inet->cork.opt = NULL;
|
|
dst_release(inet->cork.dst);
|
|
inet->cork.dst = NULL;
|
|
}
|
|
|
|
/*
|
|
* Combined all pending IP fragments on the socket as one IP datagram
|
|
* and push them out.
|
|
*/
|
|
int ip_push_pending_frames(struct sock *sk)
|
|
{
|
|
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 *)inet->cork.dst;
|
|
struct iphdr *iph;
|
|
__be16 df = 0;
|
|
__u8 ttl;
|
|
int err = 0;
|
|
|
|
if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
|
|
goto out;
|
|
tail_skb = &(skb_shinfo(skb)->frag_list);
|
|
|
|
/* move skb->data to ip header from ext header */
|
|
if (skb->data < skb_network_header(skb))
|
|
__skb_pull(skb, skb_network_offset(skb));
|
|
while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
|
|
__skb_pull(tmp_skb, skb_network_header_len(skb));
|
|
*tail_skb = tmp_skb;
|
|
tail_skb = &(tmp_skb->next);
|
|
skb->len += tmp_skb->len;
|
|
skb->data_len += tmp_skb->len;
|
|
skb->truesize += tmp_skb->truesize;
|
|
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.
|
|
*/
|
|
if (inet->pmtudisc < IP_PMTUDISC_DO)
|
|
skb->local_df = 1;
|
|
|
|
/* DF bit is set when we want to see DF on outgoing frames.
|
|
* If local_df is set too, we still allow to fragment this frame
|
|
* locally. */
|
|
if (inet->pmtudisc >= IP_PMTUDISC_DO ||
|
|
(skb->len <= dst_mtu(&rt->dst) &&
|
|
ip_dont_fragment(sk, &rt->dst)))
|
|
df = htons(IP_DF);
|
|
|
|
if (inet->cork.flags & IPCORK_OPT)
|
|
opt = inet->cork.opt;
|
|
|
|
if (rt->rt_type == RTN_MULTICAST)
|
|
ttl = inet->mc_ttl;
|
|
else
|
|
ttl = ip_select_ttl(inet, &rt->dst);
|
|
|
|
iph = (struct iphdr *)skb->data;
|
|
iph->version = 4;
|
|
iph->ihl = 5;
|
|
if (opt) {
|
|
iph->ihl += opt->optlen>>2;
|
|
ip_options_build(skb, opt, inet->cork.addr, rt, 0);
|
|
}
|
|
iph->tos = inet->tos;
|
|
iph->frag_off = df;
|
|
ip_select_ident(iph, &rt->dst, sk);
|
|
iph->ttl = ttl;
|
|
iph->protocol = sk->sk_protocol;
|
|
iph->saddr = rt->rt_src;
|
|
iph->daddr = rt->rt_dst;
|
|
|
|
skb->priority = sk->sk_priority;
|
|
skb->mark = sk->sk_mark;
|
|
/*
|
|
* Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
|
|
* on dst refcount
|
|
*/
|
|
inet->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);
|
|
|
|
/* Netfilter gets whole the not fragmented skb. */
|
|
err = ip_local_out(skb);
|
|
if (err) {
|
|
if (err > 0)
|
|
err = net_xmit_errno(err);
|
|
if (err)
|
|
goto error;
|
|
}
|
|
|
|
out:
|
|
ip_cork_release(inet);
|
|
return err;
|
|
|
|
error:
|
|
IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Throw away all pending data on the socket.
|
|
*/
|
|
void ip_flush_pending_frames(struct sock *sk)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
|
|
kfree_skb(skb);
|
|
|
|
ip_cork_release(inet_sk(sk));
|
|
}
|
|
|
|
|
|
/*
|
|
* 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, 0);
|
|
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 TCP resets so far. ICMP should use this function too.
|
|
*
|
|
* Should run single threaded per socket because it uses the sock
|
|
* structure to pass arguments.
|
|
*/
|
|
void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
|
|
unsigned int len)
|
|
{
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
struct {
|
|
struct ip_options opt;
|
|
char data[40];
|
|
} replyopts;
|
|
struct ipcm_cookie ipc;
|
|
__be32 daddr;
|
|
struct rtable *rt = skb_rtable(skb);
|
|
|
|
if (ip_options_echo(&replyopts.opt, skb))
|
|
return;
|
|
|
|
daddr = ipc.addr = rt->rt_src;
|
|
ipc.opt = NULL;
|
|
ipc.shtx.flags = 0;
|
|
|
|
if (replyopts.opt.optlen) {
|
|
ipc.opt = &replyopts.opt;
|
|
|
|
if (ipc.opt->srr)
|
|
daddr = replyopts.opt.faddr;
|
|
}
|
|
|
|
{
|
|
struct flowi fl = { .oif = arg->bound_dev_if,
|
|
.nl_u = { .ip4_u =
|
|
{ .daddr = daddr,
|
|
.saddr = rt->rt_spec_dst,
|
|
.tos = RT_TOS(ip_hdr(skb)->tos) } },
|
|
/* Not quite clean, but right. */
|
|
.uli_u = { .ports =
|
|
{ .sport = tcp_hdr(skb)->dest,
|
|
.dport = tcp_hdr(skb)->source } },
|
|
.proto = sk->sk_protocol,
|
|
.flags = ip_reply_arg_flowi_flags(arg) };
|
|
security_skb_classify_flow(skb, &fl);
|
|
if (ip_route_output_key(sock_net(sk), &rt, &fl))
|
|
return;
|
|
}
|
|
|
|
/* And let IP do all the hard work.
|
|
|
|
This chunk is not reenterable, hence spinlock.
|
|
Note that it uses the fact, that this function is called
|
|
with locally disabled BH and that sk cannot be already spinlocked.
|
|
*/
|
|
bh_lock_sock(sk);
|
|
inet->tos = ip_hdr(skb)->tos;
|
|
sk->sk_priority = skb->priority;
|
|
sk->sk_protocol = ip_hdr(skb)->protocol;
|
|
sk->sk_bound_dev_if = arg->bound_dev_if;
|
|
ip_append_data(sk, ip_reply_glue_bits, arg->iov->iov_base, len, 0,
|
|
&ipc, &rt, MSG_DONTWAIT);
|
|
if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
|
|
if (arg->csumoffset >= 0)
|
|
*((__sum16 *)skb_transport_header(skb) +
|
|
arg->csumoffset) = csum_fold(csum_add(skb->csum,
|
|
arg->csum));
|
|
skb->ip_summed = CHECKSUM_NONE;
|
|
ip_push_pending_frames(sk);
|
|
}
|
|
|
|
bh_unlock_sock(sk);
|
|
|
|
ip_rt_put(rt);
|
|
}
|
|
|
|
void __init ip_init(void)
|
|
{
|
|
ip_rt_init();
|
|
inet_initpeers();
|
|
|
|
#if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS)
|
|
igmp_mc_proc_init();
|
|
#endif
|
|
}
|