diff options
Diffstat (limited to 'net/ipv4/netfilter/ip_conntrack_proto_udp.c')
| -rw-r--r-- | net/ipv4/netfilter/ip_conntrack_proto_udp.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ip_conntrack_proto_udp.c b/net/ipv4/netfilter/ip_conntrack_proto_udp.c new file mode 100644 index 00000000000..5bc28a22462 --- /dev/null +++ b/net/ipv4/netfilter/ip_conntrack_proto_udp.c @@ -0,0 +1,146 @@ +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> + * + * 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/sched.h> +#include <linux/timer.h> +#include <linux/netfilter.h> +#include <linux/in.h> +#include <linux/udp.h> +#include <linux/seq_file.h> +#include <net/checksum.h> +#include <linux/netfilter.h> +#include <linux/netfilter_ipv4.h> +#include <linux/netfilter_ipv4/ip_conntrack_protocol.h> + +unsigned long ip_ct_udp_timeout = 30*HZ; +unsigned long ip_ct_udp_timeout_stream = 180*HZ; + +static int udp_pkt_to_tuple(const struct sk_buff *skb, + unsigned int dataoff, + struct ip_conntrack_tuple *tuple) +{ + struct udphdr _hdr, *hp; + + /* Actually only need first 8 bytes. */ + hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); + if (hp == NULL) + return 0; + + tuple->src.u.udp.port = hp->source; + tuple->dst.u.udp.port = hp->dest; + + return 1; +} + +static int udp_invert_tuple(struct ip_conntrack_tuple *tuple, + const struct ip_conntrack_tuple *orig) +{ + tuple->src.u.udp.port = orig->dst.u.udp.port; + tuple->dst.u.udp.port = orig->src.u.udp.port; + return 1; +} + +/* Print out the per-protocol part of the tuple. */ +static int udp_print_tuple(struct seq_file *s, + const struct ip_conntrack_tuple *tuple) +{ + return seq_printf(s, "sport=%hu dport=%hu ", + ntohs(tuple->src.u.udp.port), + ntohs(tuple->dst.u.udp.port)); +} + +/* Print out the private part of the conntrack. */ +static int udp_print_conntrack(struct seq_file *s, + const struct ip_conntrack *conntrack) +{ + return 0; +} + +/* Returns verdict for packet, and may modify conntracktype */ +static int udp_packet(struct ip_conntrack *conntrack, + const struct sk_buff *skb, + enum ip_conntrack_info ctinfo) +{ + /* If we've seen traffic both ways, this is some kind of UDP + stream. Extend timeout. */ + if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) { + ip_ct_refresh_acct(conntrack, ctinfo, skb, + ip_ct_udp_timeout_stream); + /* Also, more likely to be important, and not a probe */ + set_bit(IPS_ASSURED_BIT, &conntrack->status); + } else + ip_ct_refresh_acct(conntrack, ctinfo, skb, ip_ct_udp_timeout); + + return NF_ACCEPT; +} + +/* Called when a new connection for this protocol found. */ +static int udp_new(struct ip_conntrack *conntrack, const struct sk_buff *skb) +{ + return 1; +} + +static int udp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo, + unsigned int hooknum) +{ + struct iphdr *iph = skb->nh.iph; + unsigned int udplen = skb->len - iph->ihl * 4; + struct udphdr _hdr, *hdr; + + /* Header is too small? */ + hdr = skb_header_pointer(skb, iph->ihl*4, sizeof(_hdr), &_hdr); + if (hdr == NULL) { + if (LOG_INVALID(IPPROTO_UDP)) + nf_log_packet(PF_INET, 0, skb, NULL, NULL, + "ip_ct_udp: short packet "); + return -NF_ACCEPT; + } + + /* Truncated/malformed packets */ + if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) { + if (LOG_INVALID(IPPROTO_UDP)) + nf_log_packet(PF_INET, 0, skb, NULL, NULL, + "ip_ct_udp: truncated/malformed packet "); + return -NF_ACCEPT; + } + + /* Packet with no checksum */ + if (!hdr->check) + return NF_ACCEPT; + + /* Checksum invalid? Ignore. + * We skip checking packets on the outgoing path + * because the semantic of CHECKSUM_HW is different there + * and moreover root might send raw packets. + * FIXME: Source route IP option packets --RR */ + if (hooknum == NF_IP_PRE_ROUTING + && csum_tcpudp_magic(iph->saddr, iph->daddr, udplen, IPPROTO_UDP, + skb->ip_summed == CHECKSUM_HW ? skb->csum + : skb_checksum(skb, iph->ihl*4, udplen, 0))) { + if (LOG_INVALID(IPPROTO_UDP)) + nf_log_packet(PF_INET, 0, skb, NULL, NULL, + "ip_ct_udp: bad UDP checksum "); + return -NF_ACCEPT; + } + + return NF_ACCEPT; +} + +struct ip_conntrack_protocol ip_conntrack_protocol_udp = +{ + .proto = IPPROTO_UDP, + .name = "udp", + .pkt_to_tuple = udp_pkt_to_tuple, + .invert_tuple = udp_invert_tuple, + .print_tuple = udp_print_tuple, + .print_conntrack = udp_print_conntrack, + .packet = udp_packet, + .new = udp_new, + .error = udp_error, +}; |