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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-02 13:38:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-02 13:38:27 -0700
commitaecdc33e111b2c447b622e287c6003726daa1426 (patch)
tree3e7657eae4b785e1a1fb5dfb225dbae0b2f0cfc6 /net/netfilter/nf_nat_helper.c
parenta20acf99f75e49271381d65db097c9763060a1e8 (diff)
parenta3a6cab5ea10cca64d036851fe0d932448f2fe4f (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking changes from David Miller: 1) GRE now works over ipv6, from Dmitry Kozlov. 2) Make SCTP more network namespace aware, from Eric Biederman. 3) TEAM driver now works with non-ethernet devices, from Jiri Pirko. 4) Make openvswitch network namespace aware, from Pravin B Shelar. 5) IPV6 NAT implementation, from Patrick McHardy. 6) Server side support for TCP Fast Open, from Jerry Chu and others. 7) Packet BPF filter supports MOD and XOR, from Eric Dumazet and Daniel Borkmann. 8) Increate the loopback default MTU to 64K, from Eric Dumazet. 9) Use a per-task rather than per-socket page fragment allocator for outgoing networking traffic. This benefits processes that have very many mostly idle sockets, which is quite common. From Eric Dumazet. 10) Use up to 32K for page fragment allocations, with fallbacks to smaller sizes when higher order page allocations fail. Benefits are a) less segments for driver to process b) less calls to page allocator c) less waste of space. From Eric Dumazet. 11) Allow GRO to be used on GRE tunnels, from Eric Dumazet. 12) VXLAN device driver, one way to handle VLAN issues such as the limitation of 4096 VLAN IDs yet still have some level of isolation. From Stephen Hemminger. 13) As usual there is a large boatload of driver changes, with the scale perhaps tilted towards the wireless side this time around. Fix up various fairly trivial conflicts, mostly caused by the user namespace changes. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1012 commits) hyperv: Add buffer for extended info after the RNDIS response message. hyperv: Report actual status in receive completion packet hyperv: Remove extra allocated space for recv_pkt_list elements hyperv: Fix page buffer handling in rndis_filter_send_request() hyperv: Fix the missing return value in rndis_filter_set_packet_filter() hyperv: Fix the max_xfer_size in RNDIS initialization vxlan: put UDP socket in correct namespace vxlan: Depend on CONFIG_INET sfc: Fix the reported priorities of different filter types sfc: Remove EFX_FILTER_FLAG_RX_OVERRIDE_IP sfc: Fix loopback self-test with separate_tx_channels=1 sfc: Fix MCDI structure field lookup sfc: Add parentheses around use of bitfield macro arguments sfc: Fix null function pointer in efx_sriov_channel_type vxlan: virtual extensible lan igmp: export symbol ip_mc_leave_group netlink: add attributes to fdb interface tg3: unconditionally select HWMON support when tg3 is enabled. Revert "net: ti cpsw ethernet: allow reading phy interface mode from DT" gre: fix sparse warning ...
Diffstat (limited to 'net/netfilter/nf_nat_helper.c')
-rw-r--r--net/netfilter/nf_nat_helper.c435
1 files changed, 435 insertions, 0 deletions
diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c
new file mode 100644
index 000000000000..23c2b38676a6
--- /dev/null
+++ b/net/netfilter/nf_nat_helper.c
@@ -0,0 +1,435 @@
+/* nf_nat_helper.c - generic support functions for NAT helpers
+ *
+ * (C) 2000-2002 Harald Welte <laforge@netfilter.org>
+ * (C) 2003-2006 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/module.h>
+#include <linux/gfp.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <net/tcp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_ecache.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_nat_helper.h>
+
+#define DUMP_OFFSET(x) \
+ pr_debug("offset_before=%d, offset_after=%d, correction_pos=%u\n", \
+ x->offset_before, x->offset_after, x->correction_pos);
+
+static DEFINE_SPINLOCK(nf_nat_seqofs_lock);
+
+/* Setup TCP sequence correction given this change at this sequence */
+static inline void
+adjust_tcp_sequence(u32 seq,
+ int sizediff,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo)
+{
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ struct nf_conn_nat *nat = nfct_nat(ct);
+ struct nf_nat_seq *this_way = &nat->seq[dir];
+
+ pr_debug("adjust_tcp_sequence: seq = %u, sizediff = %d\n",
+ seq, sizediff);
+
+ pr_debug("adjust_tcp_sequence: Seq_offset before: ");
+ DUMP_OFFSET(this_way);
+
+ spin_lock_bh(&nf_nat_seqofs_lock);
+
+ /* SYN adjust. If it's uninitialized, or this is after last
+ * correction, record it: we don't handle more than one
+ * adjustment in the window, but do deal with common case of a
+ * retransmit */
+ if (this_way->offset_before == this_way->offset_after ||
+ before(this_way->correction_pos, seq)) {
+ this_way->correction_pos = seq;
+ this_way->offset_before = this_way->offset_after;
+ this_way->offset_after += sizediff;
+ }
+ spin_unlock_bh(&nf_nat_seqofs_lock);
+
+ pr_debug("adjust_tcp_sequence: Seq_offset after: ");
+ DUMP_OFFSET(this_way);
+}
+
+/* Get the offset value, for conntrack */
+s16 nf_nat_get_offset(const struct nf_conn *ct,
+ enum ip_conntrack_dir dir,
+ u32 seq)
+{
+ struct nf_conn_nat *nat = nfct_nat(ct);
+ struct nf_nat_seq *this_way;
+ s16 offset;
+
+ if (!nat)
+ return 0;
+
+ this_way = &nat->seq[dir];
+ spin_lock_bh(&nf_nat_seqofs_lock);
+ offset = after(seq, this_way->correction_pos)
+ ? this_way->offset_after : this_way->offset_before;
+ spin_unlock_bh(&nf_nat_seqofs_lock);
+
+ return offset;
+}
+
+/* Frobs data inside this packet, which is linear. */
+static void mangle_contents(struct sk_buff *skb,
+ unsigned int dataoff,
+ unsigned int match_offset,
+ unsigned int match_len,
+ const char *rep_buffer,
+ unsigned int rep_len)
+{
+ unsigned char *data;
+
+ BUG_ON(skb_is_nonlinear(skb));
+ data = skb_network_header(skb) + dataoff;
+
+ /* move post-replacement */
+ memmove(data + match_offset + rep_len,
+ data + match_offset + match_len,
+ skb->tail - (skb->network_header + dataoff +
+ match_offset + match_len));
+
+ /* insert data from buffer */
+ memcpy(data + match_offset, rep_buffer, rep_len);
+
+ /* update skb info */
+ if (rep_len > match_len) {
+ pr_debug("nf_nat_mangle_packet: Extending packet by "
+ "%u from %u bytes\n", rep_len - match_len, skb->len);
+ skb_put(skb, rep_len - match_len);
+ } else {
+ pr_debug("nf_nat_mangle_packet: Shrinking packet from "
+ "%u from %u bytes\n", match_len - rep_len, skb->len);
+ __skb_trim(skb, skb->len + rep_len - match_len);
+ }
+
+ if (nf_ct_l3num((struct nf_conn *)skb->nfct) == NFPROTO_IPV4) {
+ /* fix IP hdr checksum information */
+ ip_hdr(skb)->tot_len = htons(skb->len);
+ ip_send_check(ip_hdr(skb));
+ } else
+ ipv6_hdr(skb)->payload_len =
+ htons(skb->len - sizeof(struct ipv6hdr));
+}
+
+/* Unusual, but possible case. */
+static int enlarge_skb(struct sk_buff *skb, unsigned int extra)
+{
+ if (skb->len + extra > 65535)
+ return 0;
+
+ if (pskb_expand_head(skb, 0, extra - skb_tailroom(skb), GFP_ATOMIC))
+ return 0;
+
+ return 1;
+}
+
+void nf_nat_set_seq_adjust(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+ __be32 seq, s16 off)
+{
+ if (!off)
+ return;
+ set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
+ adjust_tcp_sequence(ntohl(seq), off, ct, ctinfo);
+ nf_conntrack_event_cache(IPCT_NATSEQADJ, ct);
+}
+EXPORT_SYMBOL_GPL(nf_nat_set_seq_adjust);
+
+void nf_nat_tcp_seq_adjust(struct sk_buff *skb, struct nf_conn *ct,
+ u32 ctinfo, int off)
+{
+ const struct tcphdr *th;
+
+ if (nf_ct_protonum(ct) != IPPROTO_TCP)
+ return;
+
+ th = (struct tcphdr *)(skb_network_header(skb)+ ip_hdrlen(skb));
+ nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off);
+}
+EXPORT_SYMBOL_GPL(nf_nat_tcp_seq_adjust);
+
+/* Generic function for mangling variable-length address changes inside
+ * NATed TCP connections (like the PORT XXX,XXX,XXX,XXX,XXX,XXX
+ * command in FTP).
+ *
+ * Takes care about all the nasty sequence number changes, checksumming,
+ * skb enlargement, ...
+ *
+ * */
+int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ unsigned int protoff,
+ unsigned int match_offset,
+ unsigned int match_len,
+ const char *rep_buffer,
+ unsigned int rep_len, bool adjust)
+{
+ const struct nf_nat_l3proto *l3proto;
+ struct tcphdr *tcph;
+ int oldlen, datalen;
+
+ if (!skb_make_writable(skb, skb->len))
+ return 0;
+
+ if (rep_len > match_len &&
+ rep_len - match_len > skb_tailroom(skb) &&
+ !enlarge_skb(skb, rep_len - match_len))
+ return 0;
+
+ SKB_LINEAR_ASSERT(skb);
+
+ tcph = (void *)skb->data + protoff;
+
+ oldlen = skb->len - protoff;
+ mangle_contents(skb, protoff + tcph->doff*4,
+ match_offset, match_len, rep_buffer, rep_len);
+
+ datalen = skb->len - protoff;
+
+ l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct));
+ l3proto->csum_recalc(skb, IPPROTO_TCP, tcph, &tcph->check,
+ datalen, oldlen);
+
+ if (adjust && rep_len != match_len)
+ nf_nat_set_seq_adjust(ct, ctinfo, tcph->seq,
+ (int)rep_len - (int)match_len);
+
+ return 1;
+}
+EXPORT_SYMBOL(__nf_nat_mangle_tcp_packet);
+
+/* Generic function for mangling variable-length address changes inside
+ * NATed UDP connections (like the CONNECT DATA XXXXX MESG XXXXX INDEX XXXXX
+ * command in the Amanda protocol)
+ *
+ * Takes care about all the nasty sequence number changes, checksumming,
+ * skb enlargement, ...
+ *
+ * XXX - This function could be merged with nf_nat_mangle_tcp_packet which
+ * should be fairly easy to do.
+ */
+int
+nf_nat_mangle_udp_packet(struct sk_buff *skb,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ unsigned int protoff,
+ unsigned int match_offset,
+ unsigned int match_len,
+ const char *rep_buffer,
+ unsigned int rep_len)
+{
+ const struct nf_nat_l3proto *l3proto;
+ struct udphdr *udph;
+ int datalen, oldlen;
+
+ if (!skb_make_writable(skb, skb->len))
+ return 0;
+
+ if (rep_len > match_len &&
+ rep_len - match_len > skb_tailroom(skb) &&
+ !enlarge_skb(skb, rep_len - match_len))
+ return 0;
+
+ udph = (void *)skb->data + protoff;
+
+ oldlen = skb->len - protoff;
+ mangle_contents(skb, protoff + sizeof(*udph),
+ match_offset, match_len, rep_buffer, rep_len);
+
+ /* update the length of the UDP packet */
+ datalen = skb->len - protoff;
+ udph->len = htons(datalen);
+
+ /* fix udp checksum if udp checksum was previously calculated */
+ if (!udph->check && skb->ip_summed != CHECKSUM_PARTIAL)
+ return 1;
+
+ l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct));
+ l3proto->csum_recalc(skb, IPPROTO_UDP, udph, &udph->check,
+ datalen, oldlen);
+
+ return 1;
+}
+EXPORT_SYMBOL(nf_nat_mangle_udp_packet);
+
+/* Adjust one found SACK option including checksum correction */
+static void
+sack_adjust(struct sk_buff *skb,
+ struct tcphdr *tcph,
+ unsigned int sackoff,
+ unsigned int sackend,
+ struct nf_nat_seq *natseq)
+{
+ while (sackoff < sackend) {
+ struct tcp_sack_block_wire *sack;
+ __be32 new_start_seq, new_end_seq;
+
+ sack = (void *)skb->data + sackoff;
+ if (after(ntohl(sack->start_seq) - natseq->offset_before,
+ natseq->correction_pos))
+ new_start_seq = htonl(ntohl(sack->start_seq)
+ - natseq->offset_after);
+ else
+ new_start_seq = htonl(ntohl(sack->start_seq)
+ - natseq->offset_before);
+
+ if (after(ntohl(sack->end_seq) - natseq->offset_before,
+ natseq->correction_pos))
+ new_end_seq = htonl(ntohl(sack->end_seq)
+ - natseq->offset_after);
+ else
+ new_end_seq = htonl(ntohl(sack->end_seq)
+ - natseq->offset_before);
+
+ pr_debug("sack_adjust: start_seq: %d->%d, end_seq: %d->%d\n",
+ ntohl(sack->start_seq), new_start_seq,
+ ntohl(sack->end_seq), new_end_seq);
+
+ inet_proto_csum_replace4(&tcph->check, skb,
+ sack->start_seq, new_start_seq, 0);
+ inet_proto_csum_replace4(&tcph->check, skb,
+ sack->end_seq, new_end_seq, 0);
+ sack->start_seq = new_start_seq;
+ sack->end_seq = new_end_seq;
+ sackoff += sizeof(*sack);
+ }
+}
+
+/* TCP SACK sequence number adjustment */
+static inline unsigned int
+nf_nat_sack_adjust(struct sk_buff *skb,
+ unsigned int protoff,
+ struct tcphdr *tcph,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo)
+{
+ unsigned int dir, optoff, optend;
+ struct nf_conn_nat *nat = nfct_nat(ct);
+
+ optoff = protoff + sizeof(struct tcphdr);
+ optend = protoff + tcph->doff * 4;
+
+ if (!skb_make_writable(skb, optend))
+ return 0;
+
+ dir = CTINFO2DIR(ctinfo);
+
+ while (optoff < optend) {
+ /* Usually: option, length. */
+ unsigned char *op = skb->data + optoff;
+
+ switch (op[0]) {
+ case TCPOPT_EOL:
+ return 1;
+ case TCPOPT_NOP:
+ optoff++;
+ continue;
+ default:
+ /* no partial options */
+ if (optoff + 1 == optend ||
+ optoff + op[1] > optend ||
+ op[1] < 2)
+ return 0;
+ if (op[0] == TCPOPT_SACK &&
+ op[1] >= 2+TCPOLEN_SACK_PERBLOCK &&
+ ((op[1] - 2) % TCPOLEN_SACK_PERBLOCK) == 0)
+ sack_adjust(skb, tcph, optoff+2,
+ optoff+op[1], &nat->seq[!dir]);
+ optoff += op[1];
+ }
+ }
+ return 1;
+}
+
+/* TCP sequence number adjustment. Returns 1 on success, 0 on failure */
+int
+nf_nat_seq_adjust(struct sk_buff *skb,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ unsigned int protoff)
+{
+ struct tcphdr *tcph;
+ int dir;
+ __be32 newseq, newack;
+ s16 seqoff, ackoff;
+ struct nf_conn_nat *nat = nfct_nat(ct);
+ struct nf_nat_seq *this_way, *other_way;
+
+ dir = CTINFO2DIR(ctinfo);
+
+ this_way = &nat->seq[dir];
+ other_way = &nat->seq[!dir];
+
+ if (!skb_make_writable(skb, protoff + sizeof(*tcph)))
+ return 0;
+
+ tcph = (void *)skb->data + protoff;
+ if (after(ntohl(tcph->seq), this_way->correction_pos))
+ seqoff = this_way->offset_after;
+ else
+ seqoff = this_way->offset_before;
+
+ if (after(ntohl(tcph->ack_seq) - other_way->offset_before,
+ other_way->correction_pos))
+ ackoff = other_way->offset_after;
+ else
+ ackoff = other_way->offset_before;
+
+ newseq = htonl(ntohl(tcph->seq) + seqoff);
+ newack = htonl(ntohl(tcph->ack_seq) - ackoff);
+
+ inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, 0);
+ inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq, newack, 0);
+
+ pr_debug("Adjusting sequence number from %u->%u, ack from %u->%u\n",
+ ntohl(tcph->seq), ntohl(newseq), ntohl(tcph->ack_seq),
+ ntohl(newack));
+
+ tcph->seq = newseq;
+ tcph->ack_seq = newack;
+
+ return nf_nat_sack_adjust(skb, protoff, tcph, ct, ctinfo);
+}
+
+/* Setup NAT on this expected conntrack so it follows master. */
+/* If we fail to get a free NAT slot, we'll get dropped on confirm */
+void nf_nat_follow_master(struct nf_conn *ct,
+ struct nf_conntrack_expect *exp)
+{
+ struct nf_nat_range range;
+
+ /* This must be a fresh one. */
+ BUG_ON(ct->status & IPS_NAT_DONE_MASK);
+
+ /* Change src to where master sends to */
+ range.flags = NF_NAT_RANGE_MAP_IPS;
+ range.min_addr = range.max_addr
+ = ct->master->tuplehash[!exp->dir].tuple.dst.u3;
+ nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
+
+ /* For DST manip, map port here to where it's expected. */
+ range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED);
+ range.min_proto = range.max_proto = exp->saved_proto;
+ range.min_addr = range.max_addr
+ = ct->master->tuplehash[!exp->dir].tuple.src.u3;
+ nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
+}
+EXPORT_SYMBOL(nf_nat_follow_master);