| /* |
| * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> |
| * |
| * 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/sctp.h> |
| #include <net/sctp/checksum.h> |
| |
| #include <net/netfilter/nf_nat_l4proto.h> |
| |
| static u_int16_t nf_sctp_port_rover; |
| |
| static void |
| sctp_unique_tuple(const struct nf_nat_l3proto *l3proto, |
| struct nf_conntrack_tuple *tuple, |
| const struct nf_nat_range *range, |
| enum nf_nat_manip_type maniptype, |
| const struct nf_conn *ct) |
| { |
| nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct, |
| &nf_sctp_port_rover); |
| } |
| |
| static bool |
| sctp_manip_pkt(struct sk_buff *skb, |
| const struct nf_nat_l3proto *l3proto, |
| unsigned int iphdroff, unsigned int hdroff, |
| const struct nf_conntrack_tuple *tuple, |
| enum nf_nat_manip_type maniptype) |
| { |
| struct sctphdr *hdr; |
| int hdrsize = 8; |
| |
| /* This could be an inner header returned in imcp packet; in such |
| * cases we cannot update the checksum field since it is outside |
| * of the 8 bytes of transport layer headers we are guaranteed. |
| */ |
| if (skb->len >= hdroff + sizeof(*hdr)) |
| hdrsize = sizeof(*hdr); |
| |
| if (!skb_make_writable(skb, hdroff + hdrsize)) |
| return false; |
| |
| hdr = (struct sctphdr *)(skb->data + hdroff); |
| |
| if (maniptype == NF_NAT_MANIP_SRC) { |
| /* Get rid of src port */ |
| hdr->source = tuple->src.u.sctp.port; |
| } else { |
| /* Get rid of dst port */ |
| hdr->dest = tuple->dst.u.sctp.port; |
| } |
| |
| if (hdrsize < sizeof(*hdr)) |
| return true; |
| |
| if (skb->ip_summed != CHECKSUM_PARTIAL) { |
| hdr->checksum = sctp_compute_cksum(skb, hdroff); |
| skb->ip_summed = CHECKSUM_NONE; |
| } |
| |
| return true; |
| } |
| |
| const struct nf_nat_l4proto nf_nat_l4proto_sctp = { |
| .l4proto = IPPROTO_SCTP, |
| .manip_pkt = sctp_manip_pkt, |
| .in_range = nf_nat_l4proto_in_range, |
| .unique_tuple = sctp_unique_tuple, |
| #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
| .nlattr_to_range = nf_nat_l4proto_nlattr_to_range, |
| #endif |
| }; |