cregit-Linux how code gets into the kernel

Release 4.8 net/sched/act_nat.c

Directory: net/sched
 * Stateless NAT actions
 * Copyright (c) 2007 Herbert Xu <>
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/tc_act/tc_nat.h>
#include <net/act_api.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/netlink.h>
#include <net/tc_act/tc_nat.h>
#include <net/tcp.h>
#include <net/udp.h>

#define NAT_TAB_MASK	15

static int nat_net_id;

static struct tc_action_ops act_nat_ops;

static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = {
	[TCA_NAT_PARMS]	= { .len = sizeof(struct tc_nat) },

static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est, struct tc_action **a, int ovr, int bind) { struct tc_action_net *tn = net_generic(net, nat_net_id); struct nlattr *tb[TCA_NAT_MAX + 1]; struct tc_nat *parm; int ret = 0, err; struct tcf_nat *p; if (nla == NULL) return -EINVAL; err = nla_parse_nested(tb, TCA_NAT_MAX, nla, nat_policy); if (err < 0) return err; if (tb[TCA_NAT_PARMS] == NULL) return -EINVAL; parm = nla_data(tb[TCA_NAT_PARMS]); if (!tcf_hash_check(tn, parm->index, a, bind)) { ret = tcf_hash_create(tn, parm->index, est, a, &act_nat_ops, bind, false); if (ret) return ret; ret = ACT_P_CREATED; } else { if (bind) return 0; tcf_hash_release(*a, bind); if (!ovr) return -EEXIST; } p = to_tcf_nat(*a); spin_lock_bh(&p->tcf_lock); p->old_addr = parm->old_addr; p->new_addr = parm->new_addr; p->mask = parm->mask; p->flags = parm->flags; p->tcf_action = parm->action; spin_unlock_bh(&p->tcf_lock); if (ret == ACT_P_CREATED) tcf_hash_insert(tn, *a); return ret; }


herbert xuherbert xu20571.68%19.09%
americo wangamerico wang3311.54%436.36%
patrick mchardypatrick mchardy269.09%327.27%
jamal hadi salimjamal hadi salim155.24%19.09%
benjamin lahaisebenjamin lahaise51.75%19.09%
eric dumazeteric dumazet20.70%19.09%

static int tcf_nat(struct sk_buff *skb, const struct tc_action *a, struct tcf_result *res) { struct tcf_nat *p = to_tcf_nat(a); struct iphdr *iph; __be32 old_addr; __be32 new_addr; __be32 mask; __be32 addr; int egress; int action; int ihl; int noff; spin_lock(&p->tcf_lock); tcf_lastuse_update(&p->tcf_tm); old_addr = p->old_addr; new_addr = p->new_addr; mask = p->mask; egress = p->flags & TCA_NAT_FLAG_EGRESS; action = p->tcf_action; bstats_update(&p->tcf_bstats, skb); spin_unlock(&p->tcf_lock); if (unlikely(action == TC_ACT_SHOT)) goto drop; noff = skb_network_offset(skb); if (!pskb_may_pull(skb, sizeof(*iph) + noff)) goto drop; iph = ip_hdr(skb); if (egress) addr = iph->saddr; else addr = iph->daddr; if (!((old_addr ^ addr) & mask)) { if (skb_try_make_writable(skb, sizeof(*iph) + noff)) goto drop; new_addr &= mask; new_addr |= addr & ~mask; /* Rewrite IP header */ iph = ip_hdr(skb); if (egress) iph->saddr = new_addr; else iph->daddr = new_addr; csum_replace4(&iph->check, addr, new_addr); } else if ((iph->frag_off & htons(IP_OFFSET)) || iph->protocol != IPPROTO_ICMP) { goto out; } ihl = iph->ihl * 4; /* It would be nice to share code with stateful NAT. */ switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) { case IPPROTO_TCP: { struct tcphdr *tcph; if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) || skb_try_make_writable(skb, ihl + sizeof(*tcph) + noff)) goto drop; tcph = (void *)(skb_network_header(skb) + ihl); inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, true); break; } case IPPROTO_UDP: { struct udphdr *udph; if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) || skb_try_make_writable(skb, ihl + sizeof(*udph) + noff)) goto drop; udph = (void *)(skb_network_header(skb) + ihl); if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) { inet_proto_csum_replace4(&udph->check, skb, addr, new_addr, true); if (!udph->check) udph->check = CSUM_MANGLED_0; } break; } case IPPROTO_ICMP: { struct icmphdr *icmph; if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + noff)) goto drop; icmph = (void *)(skb_network_header(skb) + ihl); if ((icmph->type != ICMP_DEST_UNREACH) && (icmph->type != ICMP_TIME_EXCEEDED) && (icmph->type != ICMP_PARAMETERPROB)) break; if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph) + noff)) goto drop; icmph = (void *)(skb_network_header(skb) + ihl); iph = (void *)(icmph + 1); if (egress) addr = iph->daddr; else addr = iph->saddr; if ((old_addr ^ addr) & mask) break; if (skb_try_make_writable(skb, ihl + sizeof(*icmph) + sizeof(*iph) + noff)) goto drop; icmph = (void *)(skb_network_header(skb) + ihl); iph = (void *)(icmph + 1); new_addr &= mask; new_addr |= addr & ~mask; /* XXX Fix up the inner checksums. */ if (egress) iph->daddr = new_addr; else iph->saddr = new_addr; inet_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr, false); break; } default: break; } out: return action; drop: spin_lock(&p->tcf_lock); p->tcf_qstats.drops++; spin_unlock(&p->tcf_lock); return TC_ACT_SHOT; }


herbert xuherbert xu67685.03%17.69%
changli gaochangli gao9511.95%430.77%
eric dumazeteric dumazet50.63%215.38%
daniel borkmanndaniel borkmann40.50%17.69%
patrick mchardypatrick mchardy40.50%17.69%
jamal hadi salimjamal hadi salim40.50%17.69%
tom herberttom herbert30.38%17.69%
americo wangamerico wang30.38%17.69%
jussi kivilinnajussi kivilinna10.13%17.69%

static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) { unsigned char *b = skb_tail_pointer(skb); struct tcf_nat *p = to_tcf_nat(a); struct tc_nat opt = { .old_addr = p->old_addr, .new_addr = p->new_addr, .mask = p->mask, .flags = p->flags, .index = p->tcf_index, .action = p->tcf_action, .refcnt = p->tcf_refcnt - ref, .bindcnt = p->tcf_bindcnt - bind, }; struct tcf_t t; if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt)) goto nla_put_failure; tcf_tm_dump(&t, &p->tcf_tm); if (nla_put_64bit(skb, TCA_NAT_TM, sizeof(t), &t, TCA_NAT_PAD)) goto nla_put_failure; return skb->len; nla_put_failure: nlmsg_trim(skb, b); return -1; }


herbert xuherbert xu13071.04%111.11%
eric dumazeteric dumazet158.20%111.11%
changli gaochangli gao137.10%111.11%
david s. millerdavid s. miller137.10%111.11%
jamal hadi salimjamal hadi salim52.73%222.22%
americo wangamerico wang31.64%111.11%
nicolas dichtelnicolas dichtel31.64%111.11%
patrick mchardypatrick mchardy10.55%111.11%

static int tcf_nat_walker(struct net *net, struct sk_buff *skb, struct netlink_callback *cb, int type, const struct tc_action_ops *ops) { struct tc_action_net *tn = net_generic(net, nat_net_id); return tcf_generic_walker(tn, skb, cb, type, ops); }


americo wangamerico wang56100.00%2100.00%

static int tcf_nat_search(struct net *net, struct tc_action **a, u32 index) { struct tc_action_net *tn = net_generic(net, nat_net_id); return tcf_hash_search(tn, a, index); }


americo wangamerico wang42100.00%2100.00%

static struct tc_action_ops act_nat_ops = { .kind = "nat", .type = TCA_ACT_NAT, .owner = THIS_MODULE, .act = tcf_nat, .dump = tcf_nat_dump, .init = tcf_nat_init, .walk = tcf_nat_walker, .lookup = tcf_nat_search, .size = sizeof(struct tcf_nat), };
static __net_init int nat_init_net(struct net *net) { struct tc_action_net *tn = net_generic(net, nat_net_id); return tc_action_net_init(tn, &act_nat_ops, NAT_TAB_MASK); }


americo wangamerico wang35100.00%1100.00%

static void __net_exit nat_exit_net(struct net *net) { struct tc_action_net *tn = net_generic(net, nat_net_id); tc_action_net_exit(tn); }


americo wangamerico wang29100.00%1100.00%

static struct pernet_operations nat_net_ops = { .init = nat_init_net, .exit = nat_exit_net, .id = &nat_net_id, .size = sizeof(struct tc_action_net), }; MODULE_DESCRIPTION("Stateless NAT actions"); MODULE_LICENSE("GPL");
static int __init nat_init_module(void) { return tcf_register_action(&act_nat_ops, &nat_net_ops); }


herbert xuherbert xu1684.21%133.33%
americo wangamerico wang315.79%266.67%

static void __exit nat_cleanup_module(void) { tcf_unregister_action(&act_nat_ops, &nat_net_ops); }


herbert xuherbert xu1583.33%150.00%
americo wangamerico wang316.67%150.00%

module_init(nat_init_module); module_exit(nat_cleanup_module);

Overall Contributors

herbert xuherbert xu115769.41%13.33%
americo wangamerico wang26716.02%516.67%
changli gaochangli gao1086.48%516.67%
patrick mchardypatrick mchardy593.54%413.33%
jamal hadi salimjamal hadi salim251.50%516.67%
eric dumazeteric dumazet221.32%413.33%
david s. millerdavid s. miller130.78%13.33%
benjamin lahaisebenjamin lahaise50.30%13.33%
daniel borkmanndaniel borkmann40.24%13.33%
tom herberttom herbert30.18%13.33%
nicolas dichtelnicolas dichtel30.18%13.33%
jussi kivilinnajussi kivilinna10.06%13.33%
Directory: net/sched
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