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Release 4.14 net/netfilter/nf_conntrack_tftp.c

Directory: net/netfilter
/* (C) 2001-2002 Magnus Boden <>
 * (C) 2006-2012 Patrick McHardy <>
 * 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.

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/in.h>
#include <linux/udp.h>
#include <linux/netfilter.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <linux/netfilter/nf_conntrack_tftp.h>

MODULE_AUTHOR("Magnus Boden <>");
MODULE_DESCRIPTION("TFTP connection tracking helper");

#define MAX_PORTS 8

static unsigned short ports[MAX_PORTS];

static unsigned int ports_c;
module_param_array(ports, ushort, &ports_c, 0400);
MODULE_PARM_DESC(ports, "Port numbers of TFTP servers");

unsigned int (*nf_nat_tftp_hook)(struct sk_buff *skb,
				 enum ip_conntrack_info ctinfo,
				 struct nf_conntrack_expect *exp) __read_mostly;


static int tftp_help(struct sk_buff *skb, unsigned int protoff, struct nf_conn *ct, enum ip_conntrack_info ctinfo) { const struct tftphdr *tfh; struct tftphdr _tftph; struct nf_conntrack_expect *exp; struct nf_conntrack_tuple *tuple; unsigned int ret = NF_ACCEPT; typeof(nf_nat_tftp_hook) nf_nat_tftp; tfh = skb_header_pointer(skb, protoff + sizeof(struct udphdr), sizeof(_tftph), &_tftph); if (tfh == NULL) return NF_ACCEPT; switch (ntohs(tfh->opcode)) { case TFTP_OPCODE_READ: case TFTP_OPCODE_WRITE: /* RRQ and WRQ works the same way */ nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); exp = nf_ct_expect_alloc(ct); if (exp == NULL) { nf_ct_helper_log(skb, ct, "cannot alloc expectation"); return NF_DROP; } tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct), &tuple->src.u3, &tuple->dst.u3, IPPROTO_UDP, NULL, &tuple->dst.u.udp.port); pr_debug("expect: "); nf_ct_dump_tuple(&exp->tuple); nf_nat_tftp = rcu_dereference(nf_nat_tftp_hook); if (nf_nat_tftp && ct->status & IPS_NAT_MASK) ret = nf_nat_tftp(skb, ctinfo, exp); else if (nf_ct_expect_related(exp) != 0) { nf_ct_helper_log(skb, ct, "cannot add expectation"); ret = NF_DROP; } nf_ct_expect_put(exp); break; case TFTP_OPCODE_DATA: case TFTP_OPCODE_ACK: pr_debug("Data/ACK opcode\n"); break; case TFTP_OPCODE_ERROR: pr_debug("Error opcode\n"); break; default: pr_debug("Unknown opcode\n"); } return ret; }


Patrick McHardy28189.49%555.56%
Pablo Neira Ayuso227.01%111.11%
Jan Engelhardt82.55%222.22%
Herbert Xu30.96%111.11%

static struct nf_conntrack_helper tftp[MAX_PORTS * 2] __read_mostly; static const struct nf_conntrack_expect_policy tftp_exp_policy = { .max_expected = 1, .timeout = 5 * 60, };
static void nf_conntrack_tftp_fini(void) { nf_conntrack_helpers_unregister(tftp, ports_c * 2); }


Patrick McHardy1270.59%150.00%
Gao Feng529.41%150.00%

static int __init nf_conntrack_tftp_init(void) { int i, ret; NF_CT_HELPER_BUILD_BUG_ON(0); if (ports_c == 0) ports[ports_c++] = TFTP_PORT; for (i = 0; i < ports_c; i++) { nf_ct_helper_init(&tftp[2 * i], AF_INET, IPPROTO_UDP, "tftp", TFTP_PORT, ports[i], i, &tftp_exp_policy, 0, tftp_help, NULL, THIS_MODULE); nf_ct_helper_init(&tftp[2 * i + 1], AF_INET6, IPPROTO_UDP, "tftp", TFTP_PORT, ports[i], i, &tftp_exp_policy, 0, tftp_help, NULL, THIS_MODULE); } ret = nf_conntrack_helpers_register(tftp, ports_c * 2); if (ret < 0) { pr_err("failed to register helpers\n"); return ret; } return 0; }


Patrick McHardy9360.39%233.33%
Gao Feng5334.42%116.67%
Florian Westphal53.25%116.67%
Pablo Neira Ayuso31.95%233.33%

module_init(nf_conntrack_tftp_init); module_exit(nf_conntrack_tftp_fini);

Overall Contributors

Patrick McHardy53982.16%635.29%
Gao Feng598.99%15.88%
Pablo Neira Ayuso375.64%423.53%
Jan Engelhardt81.22%211.76%
Florian Westphal50.76%15.88%
Herbert Xu40.61%15.88%
Yasuyuki Kozakai30.46%15.88%
Stephen Hemminger10.15%15.88%
Directory: net/netfilter
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