cregit-Linux how code gets into the kernel

Release 4.8 net/netfilter/nf_nat_proto_tcp.c

Directory: net/netfilter
/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2006 Netfilter Core Team <>
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.

#include <linux/types.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/tcp.h>

#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_l3proto.h>
#include <net/netfilter/nf_nat_l4proto.h>
#include <net/netfilter/nf_nat_core.h>

static u16 tcp_port_rover;

static void tcp_unique_tuple(const struct nf_nat_l3proto *l3proto, struct nf_conntrack_tuple *tuple, const struct nf_nat_range *range, enum nf_nat_manip_type maniptype, const struct nf_conn *ct) { nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct, &tcp_port_rover); }


jozsef kadlecsikjozsef kadlecsik3061.22%125.00%
patrick mchardypatrick mchardy1734.69%250.00%
changli gaochangli gao24.08%125.00%

static bool tcp_manip_pkt(struct sk_buff *skb, const struct nf_nat_l3proto *l3proto, unsigned int iphdroff, unsigned int hdroff, const struct nf_conntrack_tuple *tuple, enum nf_nat_manip_type maniptype) { struct tcphdr *hdr; __be16 *portptr, newport, oldport; int hdrsize = 8; /* TCP connection tracking guarantees this much */ /* this could be a inner header returned in icmp packet; in such cases we cannot update the checksum field since it is outside of the 8 bytes of transport layer headers we are guaranteed */ if (skb->len >= hdroff + sizeof(struct tcphdr)) hdrsize = sizeof(struct tcphdr); if (!skb_make_writable(skb, hdroff + hdrsize)) return false; hdr = (struct tcphdr *)(skb->data + hdroff); if (maniptype == NF_NAT_MANIP_SRC) { /* Get rid of src port */ newport = tuple->src.u.tcp.port; portptr = &hdr->source; } else { /* Get rid of dst port */ newport = tuple->dst.u.tcp.port; portptr = &hdr->dest; } oldport = *portptr; *portptr = newport; if (hdrsize < sizeof(*hdr)) return true; l3proto->csum_update(skb, iphdroff, &hdr->check, tuple, maniptype); inet_proto_csum_replace2(&hdr->check, skb, oldport, newport, false); return true; }


jozsef kadlecsikjozsef kadlecsik18584.86%114.29%
patrick mchardypatrick mchardy2310.55%342.86%
herbert xuherbert xu52.29%114.29%
jan engelhardtjan engelhardt41.83%114.29%
tom herberttom herbert10.46%114.29%

const struct nf_nat_l4proto nf_nat_l4proto_tcp = { .l4proto = IPPROTO_TCP, .manip_pkt = tcp_manip_pkt, .in_range = nf_nat_l4proto_in_range, .unique_tuple = tcp_unique_tuple, #if IS_ENABLED(CONFIG_NF_CT_NETLINK) .nlattr_to_range = nf_nat_l4proto_nlattr_to_range, #endif };

Overall Contributors

jozsef kadlecsikjozsef kadlecsik27580.17%17.14%
patrick mchardypatrick mchardy5215.16%750.00%
herbert xuherbert xu51.46%17.14%
jan engelhardtjan engelhardt41.17%17.14%
paul gortmakerpaul gortmaker30.87%17.14%
changli gaochangli gao20.58%17.14%
tom herberttom herbert10.29%17.14%
duan jiongduan jiong10.29%17.14%
Directory: net/netfilter
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