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[/] [or1k_soc_on_altera_embedded_dev_kit/] [tags/] [linux-2.6/] [linux-2.6.24_or32_unified_v2.3/] [net/] [ipv4/] [netfilter/] [nf_nat_proto_udp.c] - Rev 8
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/* (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2006 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/init.h> #include <linux/random.h> #include <linux/ip.h> #include <linux/udp.h> #include <linux/netfilter.h> #include <net/netfilter/nf_nat.h> #include <net/netfilter/nf_nat_core.h> #include <net/netfilter/nf_nat_rule.h> #include <net/netfilter/nf_nat_protocol.h> static int udp_in_range(const struct nf_conntrack_tuple *tuple, enum nf_nat_manip_type maniptype, const union nf_conntrack_man_proto *min, const union nf_conntrack_man_proto *max) { __be16 port; if (maniptype == IP_NAT_MANIP_SRC) port = tuple->src.u.udp.port; else port = tuple->dst.u.udp.port; return ntohs(port) >= ntohs(min->udp.port) && ntohs(port) <= ntohs(max->udp.port); } static int udp_unique_tuple(struct nf_conntrack_tuple *tuple, const struct nf_nat_range *range, enum nf_nat_manip_type maniptype, const struct nf_conn *ct) { static u_int16_t port; __be16 *portptr; unsigned int range_size, min, i; if (maniptype == IP_NAT_MANIP_SRC) portptr = &tuple->src.u.udp.port; else portptr = &tuple->dst.u.udp.port; /* If no range specified... */ if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)) { /* If it's dst rewrite, can't change port */ if (maniptype == IP_NAT_MANIP_DST) return 0; if (ntohs(*portptr) < 1024) { /* Loose convention: >> 512 is credential passing */ if (ntohs(*portptr)<512) { min = 1; range_size = 511 - min + 1; } else { min = 600; range_size = 1023 - min + 1; } } else { min = 1024; range_size = 65535 - 1024 + 1; } } else { min = ntohs(range->min.udp.port); range_size = ntohs(range->max.udp.port) - min + 1; } if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) port = net_random(); for (i = 0; i < range_size; i++, port++) { *portptr = htons(min + port % range_size); if (!nf_nat_used_tuple(tuple, ct)) return 1; } return 0; } static int udp_manip_pkt(struct sk_buff *skb, unsigned int iphdroff, const struct nf_conntrack_tuple *tuple, enum nf_nat_manip_type maniptype) { struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff); struct udphdr *hdr; unsigned int hdroff = iphdroff + iph->ihl*4; __be32 oldip, newip; __be16 *portptr, newport; if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) return 0; iph = (struct iphdr *)(skb->data + iphdroff); hdr = (struct udphdr *)(skb->data + hdroff); if (maniptype == IP_NAT_MANIP_SRC) { /* Get rid of src ip and src pt */ oldip = iph->saddr; newip = tuple->src.u3.ip; newport = tuple->src.u.udp.port; portptr = &hdr->source; } else { /* Get rid of dst ip and dst pt */ oldip = iph->daddr; newip = tuple->dst.u3.ip; newport = tuple->dst.u.udp.port; portptr = &hdr->dest; } if (hdr->check || skb->ip_summed == CHECKSUM_PARTIAL) { nf_proto_csum_replace4(&hdr->check, skb, oldip, newip, 1); nf_proto_csum_replace2(&hdr->check, skb, *portptr, newport, 0); if (!hdr->check) hdr->check = CSUM_MANGLED_0; } *portptr = newport; return 1; } struct nf_nat_protocol nf_nat_protocol_udp = { .name = "UDP", .protonum = IPPROTO_UDP, .me = THIS_MODULE, .manip_pkt = udp_manip_pkt, .in_range = udp_in_range, .unique_tuple = udp_unique_tuple, #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) .range_to_nlattr = nf_nat_port_range_to_nlattr, .nlattr_to_range = nf_nat_port_nlattr_to_range, #endif };