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openwrt/target/linux/generic/pending-4.4/666-Add-support-for-MAP-E-FMRs-mesh-mode.patch
Axel Neumann 65c05301c2 Re-enable arbitrary IPv6 addresses as outer ip4-in-ip6 tunnel source address 
The 666-Add-support-for-MAP-E-FMRs-mesh-mode.patch kernel patches
break the possibility for using an ip4ip6 tunnel interface as a fall
back interface accepting ip4-in-ip6 tunneled packets from any remote
address. This works out of the box with any normal (non-666-patched)
kernel and can be configured by setting up an 'ip -6 tunnel' with type
'any' or 'ip4ip6' and a remote address of '::'.

The misbehavior comes with line 290 the patch which discards all packets
that do not show the expected saddr, even if no single fmr rule was
defined and despite the validity of the saddr was already approved earlier.

Signed-off-by: Axel Neumann <neumann@cgws.de>
Acked-by: Hans Dedecker <dedeckeh@gmail.com>
2018-06-23 09:47:05 +02:00

497 lines
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From 775d6fe74d1eaec2ba387535b068dde2dc89de9e Mon Sep 17 00:00:00 2001
From: Steven Barth <steven@midlink.org>
Date: Thu, 22 May 2014 09:49:05 +0200
Subject: [PATCH] Add support for MAP-E FMRs (mesh mode)
MAP-E FMRs (draft-ietf-softwire-map-10) are rules for IPv4-communication
between MAP CEs (mesh mode) without the need to forward such data to a
border relay. This is similar to how 6rd works but for IPv4 over IPv6.
Signed-off-by: Steven Barth <cyrus@openwrt.org>
---
include/net/ip6_tunnel.h | 13 ++
include/uapi/linux/if_tunnel.h | 13 ++
net/ipv6/ip6_tunnel.c | 276 +++++++++++++++++++++++++++++++++++++++--
3 files changed, 291 insertions(+), 11 deletions(-)
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -17,6 +17,18 @@
/* determine capability on a per-packet basis */
#define IP6_TNL_F_CAP_PER_PACKET 0x40000
+/* IPv6 tunnel FMR */
+struct __ip6_tnl_fmr {
+ struct __ip6_tnl_fmr *next; /* next fmr in list */
+ struct in6_addr ip6_prefix;
+ struct in_addr ip4_prefix;
+
+ __u8 ip6_prefix_len;
+ __u8 ip4_prefix_len;
+ __u8 ea_len;
+ __u8 offset;
+};
+
struct __ip6_tnl_parm {
char name[IFNAMSIZ]; /* name of tunnel device */
int link; /* ifindex of underlying L2 interface */
@@ -27,6 +39,7 @@ struct __ip6_tnl_parm {
__u32 flags; /* tunnel flags */
struct in6_addr laddr; /* local tunnel end-point address */
struct in6_addr raddr; /* remote tunnel end-point address */
+ struct __ip6_tnl_fmr *fmrs; /* FMRs */
__be16 i_flags;
__be16 o_flags;
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -57,10 +57,23 @@ enum {
IFLA_IPTUN_ENCAP_FLAGS,
IFLA_IPTUN_ENCAP_SPORT,
IFLA_IPTUN_ENCAP_DPORT,
+ IFLA_IPTUN_FMRS,
__IFLA_IPTUN_MAX,
};
#define IFLA_IPTUN_MAX (__IFLA_IPTUN_MAX - 1)
+enum {
+ IFLA_IPTUN_FMR_UNSPEC,
+ IFLA_IPTUN_FMR_IP6_PREFIX,
+ IFLA_IPTUN_FMR_IP4_PREFIX,
+ IFLA_IPTUN_FMR_IP6_PREFIX_LEN,
+ IFLA_IPTUN_FMR_IP4_PREFIX_LEN,
+ IFLA_IPTUN_FMR_EA_LEN,
+ IFLA_IPTUN_FMR_OFFSET,
+ __IFLA_IPTUN_FMR_MAX,
+};
+#define IFLA_IPTUN_FMR_MAX (__IFLA_IPTUN_FMR_MAX - 1)
+
enum tunnel_encap_types {
TUNNEL_ENCAP_NONE,
TUNNEL_ENCAP_FOU,
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -16,6 +16,8 @@
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
+ * Changes:
+ * Steven Barth <cyrus@openwrt.org>: MAP-E FMR support
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -71,11 +73,9 @@ static bool log_ecn_error = true;
module_param(log_ecn_error, bool, 0644);
MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
-static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
+static u32 HASH(const struct in6_addr *addr)
{
- u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);
-
- return hash_32(hash, HASH_SIZE_SHIFT);
+ return hash_32(ipv6_addr_hash(addr), HASH_SIZE_SHIFT);
}
static int ip6_tnl_dev_init(struct net_device *dev);
@@ -139,20 +139,29 @@ static struct net_device_stats *ip6_get_
static struct ip6_tnl *
ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local)
{
- unsigned int hash = HASH(remote, local);
+ unsigned int hash = HASH(local);
struct ip6_tnl *t;
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
struct in6_addr any;
+ struct __ip6_tnl_fmr *fmr;
for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
- if (ipv6_addr_equal(local, &t->parms.laddr) &&
- ipv6_addr_equal(remote, &t->parms.raddr) &&
- (t->dev->flags & IFF_UP))
+ if (!ipv6_addr_equal(local, &t->parms.laddr) ||
+ !(t->dev->flags & IFF_UP))
+ continue;
+
+ if (ipv6_addr_equal(remote, &t->parms.raddr))
return t;
+
+ for (fmr = t->parms.fmrs; fmr; fmr = fmr->next) {
+ if (ipv6_prefix_equal(remote, &fmr->ip6_prefix,
+ fmr->ip6_prefix_len))
+ return t;
+ }
}
memset(&any, 0, sizeof(any));
- hash = HASH(&any, local);
+ hash = HASH(local);
for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
if (ipv6_addr_equal(local, &t->parms.laddr) &&
ipv6_addr_any(&t->parms.raddr) &&
@@ -160,7 +169,7 @@ ip6_tnl_lookup(struct net *net, const st
return t;
}
- hash = HASH(remote, &any);
+ hash = HASH(&any);
for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
if (ipv6_addr_equal(remote, &t->parms.raddr) &&
ipv6_addr_any(&t->parms.laddr) &&
@@ -196,7 +205,7 @@ ip6_tnl_bucket(struct ip6_tnl_net *ip6n,
if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
prio = 1;
- h = HASH(remote, local);
+ h = HASH(local);
}
return &ip6n->tnls[prio][h];
}
@@ -369,6 +378,12 @@ ip6_tnl_dev_uninit(struct net_device *de
struct net *net = t->net;
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+ while (t->parms.fmrs) {
+ struct __ip6_tnl_fmr *next = t->parms.fmrs->next;
+ kfree(t->parms.fmrs);
+ t->parms.fmrs = next;
+ }
+
if (dev == ip6n->fb_tnl_dev)
RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
else
@@ -765,6 +780,108 @@ int ip6_tnl_rcv_ctl(struct ip6_tnl *t,
}
EXPORT_SYMBOL_GPL(ip6_tnl_rcv_ctl);
+
+/**
+ * ip4ip6_fmr_calc - calculate target / source IPv6-address based on FMR
+ * @dest: destination IPv6 address buffer
+ * @skb: received socket buffer
+ * @fmr: MAP FMR
+ * @xmit: Calculate for xmit or rcv
+ **/
+static void ip4ip6_fmr_calc(struct in6_addr *dest,
+ const struct iphdr *iph, const uint8_t *end,
+ const struct __ip6_tnl_fmr *fmr, bool xmit)
+{
+ int psidlen = fmr->ea_len - (32 - fmr->ip4_prefix_len);
+ u8 *portp = NULL;
+ bool use_dest_addr;
+ const struct iphdr *dsth = iph;
+
+ if ((u8*)dsth >= end)
+ return;
+
+ /* find significant IP header */
+ if (iph->protocol == IPPROTO_ICMP) {
+ struct icmphdr *ih = (struct icmphdr*)(((u8*)dsth) + dsth->ihl * 4);
+ if (ih && ((u8*)&ih[1]) <= end && (
+ ih->type == ICMP_DEST_UNREACH ||
+ ih->type == ICMP_SOURCE_QUENCH ||
+ ih->type == ICMP_TIME_EXCEEDED ||
+ ih->type == ICMP_PARAMETERPROB ||
+ ih->type == ICMP_REDIRECT))
+ dsth = (const struct iphdr*)&ih[1];
+ }
+
+ /* in xmit-path use dest port by default and source port only if
+ this is an ICMP reply to something else; vice versa in rcv-path */
+ use_dest_addr = (xmit && dsth == iph) || (!xmit && dsth != iph);
+
+ /* get dst port */
+ if (((u8*)&dsth[1]) <= end && (
+ dsth->protocol == IPPROTO_UDP ||
+ dsth->protocol == IPPROTO_TCP ||
+ dsth->protocol == IPPROTO_SCTP ||
+ dsth->protocol == IPPROTO_DCCP)) {
+ /* for UDP, TCP, SCTP and DCCP source and dest port
+ follow IPv4 header directly */
+ portp = ((u8*)dsth) + dsth->ihl * 4;
+
+ if (use_dest_addr)
+ portp += sizeof(u16);
+ } else if (iph->protocol == IPPROTO_ICMP) {
+ struct icmphdr *ih = (struct icmphdr*)(((u8*)dsth) + dsth->ihl * 4);
+
+ /* use icmp identifier as port */
+ if (((u8*)&ih) <= end && (
+ (use_dest_addr && (
+ ih->type == ICMP_ECHOREPLY ||
+ ih->type == ICMP_TIMESTAMPREPLY ||
+ ih->type == ICMP_INFO_REPLY ||
+ ih->type == ICMP_ADDRESSREPLY)) ||
+ (!use_dest_addr && (
+ ih->type == ICMP_ECHO ||
+ ih->type == ICMP_TIMESTAMP ||
+ ih->type == ICMP_INFO_REQUEST ||
+ ih->type == ICMP_ADDRESS)
+ )))
+ portp = (u8*)&ih->un.echo.id;
+ }
+
+ if ((portp && &portp[2] <= end) || psidlen == 0) {
+ int frombyte = fmr->ip6_prefix_len / 8;
+ int fromrem = fmr->ip6_prefix_len % 8;
+ int bytes = sizeof(struct in6_addr) - frombyte;
+ const u32 *addr = (use_dest_addr) ? &iph->daddr : &iph->saddr;
+ u64 eabits = ((u64)ntohl(*addr)) << (32 + fmr->ip4_prefix_len);
+ u64 t = 0;
+
+ /* extract PSID from port and add it to eabits */
+ u16 psidbits = 0;
+ if (psidlen > 0) {
+ psidbits = ((u16)portp[0]) << 8 | ((u16)portp[1]);
+ psidbits >>= 16 - psidlen - fmr->offset;
+ psidbits = (u16)(psidbits << (16 - psidlen));
+ eabits |= ((u64)psidbits) << (48 - (fmr->ea_len - psidlen));
+ }
+
+ /* rewrite destination address */
+ *dest = fmr->ip6_prefix;
+ memcpy(&dest->s6_addr[10], addr, sizeof(*addr));
+ dest->s6_addr16[7] = htons(psidbits >> (16 - psidlen));
+
+ if (bytes > sizeof(u64))
+ bytes = sizeof(u64);
+
+ /* insert eabits */
+ memcpy(&t, &dest->s6_addr[frombyte], bytes);
+ t = be64_to_cpu(t) & ~(((((u64)1) << fmr->ea_len) - 1)
+ << (64 - fmr->ea_len - fromrem));
+ t = cpu_to_be64(t | (eabits >> fromrem));
+ memcpy(&dest->s6_addr[frombyte], &t, bytes);
+ }
+}
+
+
/**
* ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
* @skb: received socket buffer
@@ -810,6 +927,26 @@ static int ip6_tnl_rcv(struct sk_buff *s
skb_reset_network_header(skb);
skb->protocol = htons(protocol);
memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
+ if (protocol == ETH_P_IP && t->parms.fmrs &&
+ !ipv6_addr_equal(&ipv6h->saddr, &t->parms.raddr)) {
+ /* Packet didn't come from BR, so lookup FMR */
+ struct __ip6_tnl_fmr *fmr;
+ struct in6_addr expected = t->parms.raddr;
+ for (fmr = t->parms.fmrs; fmr; fmr = fmr->next)
+ if (ipv6_prefix_equal(&ipv6h->saddr,
+ &fmr->ip6_prefix, fmr->ip6_prefix_len))
+ break;
+
+ /* Check that IPv6 matches IPv4 source to prevent spoofing */
+ if (fmr)
+ ip4ip6_fmr_calc(&expected, ip_hdr(skb),
+ skb_tail_pointer(skb), fmr, false);
+
+ if (!ipv6_addr_equal(&ipv6h->saddr, &expected)) {
+ rcu_read_unlock();
+ goto discard;
+ }
+ }
__skb_tunnel_rx(skb, t->dev, t->net);
@@ -1145,6 +1282,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, str
__u32 mtu;
u8 tproto;
int err;
+ struct __ip6_tnl_fmr *fmr;
tproto = ACCESS_ONCE(t->parms.proto);
if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
@@ -1175,6 +1313,18 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, str
if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
fl6.flowi6_mark = skb->mark;
+ /* try to find matching FMR */
+ for (fmr = t->parms.fmrs; fmr; fmr = fmr->next) {
+ unsigned mshift = 32 - fmr->ip4_prefix_len;
+ if (ntohl(fmr->ip4_prefix.s_addr) >> mshift ==
+ ntohl(ip_hdr(skb)->daddr) >> mshift)
+ break;
+ }
+
+ /* change dstaddr according to FMR */
+ if (fmr)
+ ip4ip6_fmr_calc(&fl6.daddr, ip_hdr(skb), skb_tail_pointer(skb), fmr, true);
+
err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
if (err != 0) {
if (err == -EMSGSIZE)
@@ -1289,6 +1439,14 @@ ip6_tnl_change(struct ip6_tnl *t, const
t->parms.flowinfo = p->flowinfo;
t->parms.link = p->link;
t->parms.proto = p->proto;
+
+ while (t->parms.fmrs) {
+ struct __ip6_tnl_fmr *next = t->parms.fmrs->next;
+ kfree(t->parms.fmrs);
+ t->parms.fmrs = next;
+ }
+ t->parms.fmrs = p->fmrs;
+
dst_cache_reset(&t->dst_cache);
ip6_tnl_link_config(t);
return 0;
@@ -1327,6 +1485,7 @@ ip6_tnl_parm_from_user(struct __ip6_tnl_
p->flowinfo = u->flowinfo;
p->link = u->link;
p->proto = u->proto;
+ p->fmrs = NULL;
memcpy(p->name, u->name, sizeof(u->name));
}
@@ -1622,6 +1781,15 @@ static int ip6_tnl_validate(struct nlatt
return 0;
}
+static const struct nla_policy ip6_tnl_fmr_policy[IFLA_IPTUN_FMR_MAX + 1] = {
+ [IFLA_IPTUN_FMR_IP6_PREFIX] = { .len = sizeof(struct in6_addr) },
+ [IFLA_IPTUN_FMR_IP4_PREFIX] = { .len = sizeof(struct in_addr) },
+ [IFLA_IPTUN_FMR_IP6_PREFIX_LEN] = { .type = NLA_U8 },
+ [IFLA_IPTUN_FMR_IP4_PREFIX_LEN] = { .type = NLA_U8 },
+ [IFLA_IPTUN_FMR_EA_LEN] = { .type = NLA_U8 },
+ [IFLA_IPTUN_FMR_OFFSET] = { .type = NLA_U8 }
+};
+
static void ip6_tnl_netlink_parms(struct nlattr *data[],
struct __ip6_tnl_parm *parms)
{
@@ -1653,6 +1821,46 @@ static void ip6_tnl_netlink_parms(struct
if (data[IFLA_IPTUN_PROTO])
parms->proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
+
+ if (data[IFLA_IPTUN_FMRS]) {
+ unsigned rem;
+ struct nlattr *fmr;
+ nla_for_each_nested(fmr, data[IFLA_IPTUN_FMRS], rem) {
+ struct nlattr *fmrd[IFLA_IPTUN_FMR_MAX + 1], *c;
+ struct __ip6_tnl_fmr *nfmr;
+
+ nla_parse_nested(fmrd, IFLA_IPTUN_FMR_MAX,
+ fmr, ip6_tnl_fmr_policy);
+
+ if (!(nfmr = kzalloc(sizeof(*nfmr), GFP_KERNEL)))
+ continue;
+
+ nfmr->offset = 6;
+
+ if ((c = fmrd[IFLA_IPTUN_FMR_IP6_PREFIX]))
+ nla_memcpy(&nfmr->ip6_prefix, fmrd[IFLA_IPTUN_FMR_IP6_PREFIX],
+ sizeof(nfmr->ip6_prefix));
+
+ if ((c = fmrd[IFLA_IPTUN_FMR_IP4_PREFIX]))
+ nla_memcpy(&nfmr->ip4_prefix, fmrd[IFLA_IPTUN_FMR_IP4_PREFIX],
+ sizeof(nfmr->ip4_prefix));
+
+ if ((c = fmrd[IFLA_IPTUN_FMR_IP6_PREFIX_LEN]))
+ nfmr->ip6_prefix_len = nla_get_u8(c);
+
+ if ((c = fmrd[IFLA_IPTUN_FMR_IP4_PREFIX_LEN]))
+ nfmr->ip4_prefix_len = nla_get_u8(c);
+
+ if ((c = fmrd[IFLA_IPTUN_FMR_EA_LEN]))
+ nfmr->ea_len = nla_get_u8(c);
+
+ if ((c = fmrd[IFLA_IPTUN_FMR_OFFSET]))
+ nfmr->offset = nla_get_u8(c);
+
+ nfmr->next = parms->fmrs;
+ parms->fmrs = nfmr;
+ }
+ }
}
static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
@@ -1705,6 +1913,12 @@ static void ip6_tnl_dellink(struct net_d
static size_t ip6_tnl_get_size(const struct net_device *dev)
{
+ const struct ip6_tnl *t = netdev_priv(dev);
+ struct __ip6_tnl_fmr *c;
+ int fmrs = 0;
+ for (c = t->parms.fmrs; c; c = c->next)
+ ++fmrs;
+
return
/* IFLA_IPTUN_LINK */
nla_total_size(4) +
@@ -1722,6 +1936,24 @@ static size_t ip6_tnl_get_size(const str
nla_total_size(4) +
/* IFLA_IPTUN_PROTO */
nla_total_size(1) +
+ /* IFLA_IPTUN_FMRS */
+ nla_total_size(0) +
+ (
+ /* nest */
+ nla_total_size(0) +
+ /* IFLA_IPTUN_FMR_IP6_PREFIX */
+ nla_total_size(sizeof(struct in6_addr)) +
+ /* IFLA_IPTUN_FMR_IP4_PREFIX */
+ nla_total_size(sizeof(struct in_addr)) +
+ /* IFLA_IPTUN_FMR_EA_LEN */
+ nla_total_size(1) +
+ /* IFLA_IPTUN_FMR_IP6_PREFIX_LEN */
+ nla_total_size(1) +
+ /* IFLA_IPTUN_FMR_IP4_PREFIX_LEN */
+ nla_total_size(1) +
+ /* IFLA_IPTUN_FMR_OFFSET */
+ nla_total_size(1)
+ ) * fmrs +
0;
}
@@ -1729,6 +1961,9 @@ static int ip6_tnl_fill_info(struct sk_b
{
struct ip6_tnl *tunnel = netdev_priv(dev);
struct __ip6_tnl_parm *parm = &tunnel->parms;
+ struct __ip6_tnl_fmr *c;
+ int fmrcnt = 0;
+ struct nlattr *fmrs;
if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
nla_put_in6_addr(skb, IFLA_IPTUN_LOCAL, &parm->laddr) ||
@@ -1737,8 +1972,27 @@ static int ip6_tnl_fill_info(struct sk_b
nla_put_u8(skb, IFLA_IPTUN_ENCAP_LIMIT, parm->encap_limit) ||
nla_put_be32(skb, IFLA_IPTUN_FLOWINFO, parm->flowinfo) ||
nla_put_u32(skb, IFLA_IPTUN_FLAGS, parm->flags) ||
- nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->proto))
+ nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->proto) ||
+ !(fmrs = nla_nest_start(skb, IFLA_IPTUN_FMRS)))
goto nla_put_failure;
+
+ for (c = parm->fmrs; c; c = c->next) {
+ struct nlattr *fmr = nla_nest_start(skb, ++fmrcnt);
+ if (!fmr ||
+ nla_put(skb, IFLA_IPTUN_FMR_IP6_PREFIX,
+ sizeof(c->ip6_prefix), &c->ip6_prefix) ||
+ nla_put(skb, IFLA_IPTUN_FMR_IP4_PREFIX,
+ sizeof(c->ip4_prefix), &c->ip4_prefix) ||
+ nla_put_u8(skb, IFLA_IPTUN_FMR_IP6_PREFIX_LEN, c->ip6_prefix_len) ||
+ nla_put_u8(skb, IFLA_IPTUN_FMR_IP4_PREFIX_LEN, c->ip4_prefix_len) ||
+ nla_put_u8(skb, IFLA_IPTUN_FMR_EA_LEN, c->ea_len) ||
+ nla_put_u8(skb, IFLA_IPTUN_FMR_OFFSET, c->offset))
+ goto nla_put_failure;
+
+ nla_nest_end(skb, fmr);
+ }
+ nla_nest_end(skb, fmrs);
+
return 0;
nla_put_failure:
@@ -1762,6 +2016,7 @@ static const struct nla_policy ip6_tnl_p
[IFLA_IPTUN_FLOWINFO] = { .type = NLA_U32 },
[IFLA_IPTUN_FLAGS] = { .type = NLA_U32 },
[IFLA_IPTUN_PROTO] = { .type = NLA_U8 },
+ [IFLA_IPTUN_FMRS] = { .type = NLA_NESTED },
};
static struct rtnl_link_ops ip6_link_ops __read_mostly = {
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