cregit-Linux how code gets into the kernel

Release 4.11 net/netfilter/nf_queue.c

Directory: net/netfilter
/*
 * Rusty Russell (C)2000 -- This code is GPL.
 * Patrick McHardy (c) 2006-2012
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/netfilter_bridge.h>
#include <linux/seq_file.h>
#include <linux/rcupdate.h>
#include <net/protocol.h>
#include <net/netfilter/nf_queue.h>
#include <net/dst.h>

#include "nf_internals.h"

/*
 * Hook for nfnetlink_queue to register its queue handler.
 * We do this so that most of the NFQUEUE code can be modular.
 *
 * Once the queue is registered it must reinject all packets it
 * receives, no matter what.
 */

/* return EBUSY when somebody else is registered, return EEXIST if the
 * same handler is registered, return 0 in case of success. */

void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh) { /* should never happen, we only have one queueing backend in kernel */ WARN_ON(rcu_access_pointer(net->nf.queue_handler)); rcu_assign_pointer(net->nf.queue_handler, qh); }

Contributors

PersonTokensPropCommitsCommitProp
Harald Welte1435.00%225.00%
Eric W. Biedermann1332.50%112.50%
Eric Dumazet512.50%225.00%
Florian Westphal410.00%112.50%
Yasuyuki Kozakai37.50%112.50%
Patrick McHardy12.50%112.50%
Total40100.00%8100.00%

EXPORT_SYMBOL(nf_register_queue_handler); /* The caller must flush their queue before this */
void nf_unregister_queue_handler(struct net *net) { RCU_INIT_POINTER(net->nf.queue_handler, NULL); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann838.10%120.00%
Harald Welte838.10%120.00%
Yasuyuki Kozakai314.29%120.00%
Florian Westphal14.76%120.00%
Stephen Hemminger14.76%120.00%
Total21100.00%5100.00%

EXPORT_SYMBOL(nf_unregister_queue_handler);
void nf_queue_entry_release_refs(struct nf_queue_entry *entry) { struct nf_hook_state *state = &entry->state; /* Release those devices we held, or Alexey will kill me. */ if (state->in) dev_put(state->in); if (state->out) dev_put(state->out); if (state->sk) sock_put(state->sk); #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) if (entry->skb->nf_bridge) { struct net_device *physdev; physdev = nf_bridge_get_physindev(entry->skb); if (physdev) dev_put(physdev); physdev = nf_bridge_get_physoutdev(entry->skb); if (physdev) dev_put(physdev); } #endif }

Contributors

PersonTokensPropCommitsCommitProp
Patrick McHardy6453.78%120.00%
David S. Miller2924.37%240.00%
Florian Westphal2117.65%120.00%
Pablo Neira Ayuso54.20%120.00%
Total119100.00%5100.00%

EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs); /* Bump dev refs so they don't vanish while packet is out */
void nf_queue_entry_get_refs(struct nf_queue_entry *entry) { struct nf_hook_state *state = &entry->state; if (state->in) dev_hold(state->in); if (state->out) dev_hold(state->out); if (state->sk) sock_hold(state->sk); #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) if (entry->skb->nf_bridge) { struct net_device *physdev; physdev = nf_bridge_get_physindev(entry->skb); if (physdev) dev_hold(physdev); physdev = nf_bridge_get_physoutdev(entry->skb); if (physdev) dev_hold(physdev); } #endif }

Contributors

PersonTokensPropCommitsCommitProp
Florian Westphal8471.19%350.00%
David S. Miller2924.58%233.33%
Pablo Neira Ayuso54.24%116.67%
Total118100.00%6100.00%

EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_entry *entry) { const struct nf_queue_handler *qh; rcu_read_lock(); qh = rcu_dereference(net->nf.queue_handler); if (qh) qh->nf_hook_drop(net, entry); rcu_read_unlock(); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann4382.69%250.00%
Pablo Neira Ayuso59.62%125.00%
Aaron Conole47.69%125.00%
Total52100.00%4100.00%


static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state, struct nf_hook_entry *hook_entry, unsigned int queuenum) { int status = -ENOENT; struct nf_queue_entry *entry = NULL; const struct nf_afinfo *afinfo; const struct nf_queue_handler *qh; struct net *net = state->net; /* QUEUE == DROP if no one is waiting, to be safe. */ qh = rcu_dereference(net->nf.queue_handler); if (!qh) { status = -ESRCH; goto err; } afinfo = nf_get_afinfo(state->pf); if (!afinfo) goto err; entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC); if (!entry) { status = -ENOMEM; goto err; } *entry = (struct nf_queue_entry) { .skb = skb, .state = *state, .hook = hook_entry, .size = sizeof(*entry) + afinfo->route_key_size, }; nf_queue_entry_get_refs(entry); skb_dst_force(skb); afinfo->saveroute(skb, entry); status = qh->outfn(entry, queuenum); if (status < 0) { nf_queue_entry_release_refs(entry); goto err; } return 0; err: kfree(entry); return status; }

Contributors

PersonTokensPropCommitsCommitProp
Harald Welte8436.05%28.70%
Patrick McHardy6226.61%730.43%
Florian Westphal3715.88%626.09%
Pablo Neira Ayuso135.58%28.70%
Eric W. Biedermann135.58%14.35%
Yasuyuki Kozakai114.72%14.35%
David S. Miller73.00%28.70%
Eric Dumazet52.15%14.35%
Lucas De Marchi10.43%14.35%
Total233100.00%23100.00%

/* Packets leaving via this function must come back through nf_reinject(). */
int nf_queue(struct sk_buff *skb, struct nf_hook_state *state, struct nf_hook_entry **entryp, unsigned int verdict) { struct nf_hook_entry *entry = *entryp; int ret; ret = __nf_queue(skb, state, entry, verdict >> NF_VERDICT_QBITS); if (ret < 0) { if (ret == -ESRCH && (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS)) { *entryp = rcu_dereference(entry->next); return 1; } kfree_skb(skb); } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso95100.00%2100.00%
Total95100.00%2100.00%


static unsigned int nf_iterate(struct sk_buff *skb, struct nf_hook_state *state, struct nf_hook_entry **entryp) { unsigned int verdict; do { repeat: verdict = nf_hook_entry_hookfn((*entryp), skb, state); if (verdict != NF_ACCEPT) { if (verdict != NF_REPEAT) return verdict; goto repeat; } *entryp = rcu_dereference((*entryp)->next); } while (*entryp); return NF_ACCEPT; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso8798.86%150.00%
Aaron Conole11.14%150.00%
Total88100.00%2100.00%


void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict) { struct nf_hook_entry *hook_entry = entry->hook; struct sk_buff *skb = entry->skb; const struct nf_afinfo *afinfo; int err; nf_queue_entry_release_refs(entry); /* Continue traversal iff userspace said ok... */ if (verdict == NF_REPEAT) verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state); if (verdict == NF_ACCEPT) { afinfo = nf_get_afinfo(entry->state.pf); if (!afinfo || afinfo->reroute(entry->state.net, skb, entry) < 0) verdict = NF_DROP; } if (verdict == NF_ACCEPT) { hook_entry = rcu_dereference(hook_entry->next); if (hook_entry) next_hook: verdict = nf_iterate(skb, &entry->state, &hook_entry); } switch (verdict & NF_VERDICT_MASK) { case NF_ACCEPT: case NF_STOP: okfn: local_bh_disable(); entry->state.okfn(entry->state.net, entry->state.sk, skb); local_bh_enable(); break; case NF_QUEUE: err = nf_queue(skb, &entry->state, &hook_entry, verdict); if (err == 1) { if (hook_entry) goto next_hook; goto okfn; } break; case NF_STOLEN: break; default: kfree_skb(skb); } kfree(entry); }

Contributors

PersonTokensPropCommitsCommitProp
Harald Welte8835.48%14.00%
Patrick McHardy6325.40%728.00%
Pablo Neira Ayuso3012.10%28.00%
Florian Westphal2510.08%520.00%
David S. Miller145.65%312.00%
Eric W. Biedermann124.84%28.00%
Aaron Conole83.23%28.00%
Michael Wang41.61%14.00%
Eric Dumazet31.21%14.00%
Julian Anastasov10.40%14.00%
Total248100.00%25100.00%

EXPORT_SYMBOL(nf_reinject);

Overall Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso24122.17%510.20%
Harald Welte23821.90%36.12%
Patrick McHardy19718.12%1122.45%
Florian Westphal18717.20%1020.41%
Eric W. Biedermann898.19%48.16%
David S. Miller797.27%48.16%
Yasuyuki Kozakai171.56%12.04%
Eric Dumazet161.47%48.16%
Aaron Conole131.20%24.08%
Michael Wang40.37%12.04%
Tejun Heo30.28%12.04%
Julian Anastasov10.09%12.04%
Lucas De Marchi10.09%12.04%
Stephen Hemminger10.09%12.04%
Total1087100.00%49100.00%
Directory: net/netfilter
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