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Date: Fri, 5 Apr 2019 16:30:40 -0700
From: David Ahern <dsahern@...nel.org>
To: davem@...emloft.net, netdev@...r.kernel.org
Cc: idosch@...lanox.com, jiri@...lanox.com,
David Ahern <dsahern@...il.com>
Subject: [PATCH v2 net-next 17/18] ipv4: Allow ipv6 gateway with ipv4 routes
From: David Ahern <dsahern@...il.com>
Add support for RTA_VIA and allow an IPv6 nexthop for v4 routes:
$ ip ro add 172.16.1.0/24 via inet6 2001:db8::1 dev eth0
$ ip ro ls
...
172.16.1.0/24 via inet6 2001:db8::1 dev eth0
For convenience and simplicity, userspace can use RTA_VIA to specify
AF_INET or AF_INET6 gateway.
The common fib_nexthop_info dump function compares the gateway address
family to the nh_common family to know if the gateway should be encoded
as RTA_VIA or RTA_GATEWAY.
Signed-off-by: David Ahern <dsahern@...il.com>
---
include/net/ip_fib.h | 2 ++
net/ipv4/fib_frontend.c | 60 ++++++++++++++++++++++++++++++++++++++---
net/ipv4/fib_semantics.c | 69 ++++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 123 insertions(+), 8 deletions(-)
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 337106469ec5..d8195c77e247 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -401,6 +401,8 @@ static inline bool fib4_rules_early_flow_dissect(struct net *net,
/* Exported by fib_frontend.c */
extern const struct nla_policy rtm_ipv4_policy[];
void ip_fib_init(void);
+int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
+ struct netlink_ext_ack *extack);
__be32 fib_compute_spec_dst(struct sk_buff *skb);
bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev);
int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index f99a2ec32505..310060e67790 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -665,10 +665,55 @@ const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
[RTA_DPORT] = { .type = NLA_U16 },
};
+int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
+ struct netlink_ext_ack *extack)
+{
+ struct rtvia *via;
+ int alen;
+
+ if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
+ NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
+ return -EINVAL;
+ }
+
+ via = nla_data(nla);
+ alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
+
+ switch (via->rtvia_family) {
+ case AF_INET:
+ if (alen != sizeof(__be32)) {
+ NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
+ return -EINVAL;
+ }
+ cfg->fc_gw_family = AF_INET;
+ cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
+ break;
+ case AF_INET6:
+#ifdef CONFIG_IPV6
+ if (alen != sizeof(struct in6_addr)) {
+ NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
+ return -EINVAL;
+ }
+ cfg->fc_gw_family = AF_INET6;
+ cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
+#else
+ NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
+ return -EINVAL;
+#endif
+ break;
+ default:
+ NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
struct nlmsghdr *nlh, struct fib_config *cfg,
struct netlink_ext_ack *extack)
{
+ bool has_gw = false, has_via = false;
struct nlattr *attr;
int err, remaining;
struct rtmsg *rtm;
@@ -709,13 +754,16 @@ static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
cfg->fc_oif = nla_get_u32(attr);
break;
case RTA_GATEWAY:
+ has_gw = true;
cfg->fc_gw_family = AF_INET;
cfg->fc_gw4 = nla_get_be32(attr);
break;
case RTA_VIA:
- NL_SET_ERR_MSG(extack, "IPv4 does not support RTA_VIA attribute");
- err = -EINVAL;
- goto errout;
+ has_via = true;
+ err = fib_gw_from_via(cfg, attr, extack);
+ if (err)
+ goto errout;
+ break;
case RTA_PRIORITY:
cfg->fc_priority = nla_get_u32(attr);
break;
@@ -754,6 +802,12 @@ static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
}
}
+ if (has_gw && has_via) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop configuration can not contain both GATEWAY and VIA");
+ goto errout;
+ }
+
return 0;
errout:
return err;
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 4a968e24507b..017273885eee 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -606,12 +606,22 @@ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
- struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
+ struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
+ nlav = nla_find(attrs, attrlen, RTA_VIA);
+ if (nla && nlav) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop configuration can not contain both GATEWAY and VIA");
+ return -EINVAL;
+ }
if (nla) {
fib_cfg.fc_gw_family = AF_INET;
fib_cfg.fc_gw4 = nla_get_in_addr(nla);
+ } else if (nlav) {
+ ret = fib_gw_from_via(&fib_cfg, nlav, extack);
+ if (ret)
+ goto errout;
}
nla = nla_find(attrs, attrlen, RTA_FLOW);
@@ -792,11 +802,43 @@ int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
- struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
+ struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
- if (nla && nla_get_in_addr(nla) != nh->fib_nh_gw4)
- return 1;
+ nlav = nla_find(attrs, attrlen, RTA_VIA);
+ if (nla && nlav) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop configuration can not contain both GATEWAY and VIA");
+ return -EINVAL;
+ }
+
+ if (nla) {
+ if (nh->fib_nh_gw_family != AF_INET ||
+ nla_get_in_addr(nla) != nh->fib_nh_gw4)
+ return 1;
+ } else if (nlav) {
+ struct fib_config cfg2;
+ int err;
+
+ err = fib_gw_from_via(&cfg2, nlav, extack);
+ if (err)
+ return err;
+
+ switch (nh->fib_nh_gw_family) {
+ case AF_INET:
+ if (cfg2.fc_gw_family != AF_INET ||
+ cfg2.fc_gw4 != nh->fib_nh_gw4)
+ return 1;
+ break;
+ case AF_INET6:
+ if (cfg2.fc_gw_family != AF_INET6 ||
+ ipv6_addr_cmp(&cfg2.fc_gw6,
+ &nh->fib_nh_gw6))
+ return 1;
+ break;
+ }
+ }
+
#ifdef CONFIG_IP_ROUTE_CLASSID
nla = nla_find(attrs, attrlen, RTA_FLOW);
if (nla && nla_get_u32(nla) != nh->nh_tclassid)
@@ -1429,8 +1471,25 @@ int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
goto nla_put_failure;
break;
case AF_INET6:
- if (nla_put_in6_addr(skb, RTA_GATEWAY, &nhc->nhc_gw.ipv6) < 0)
+ /* if gateway family does not match nexthop family
+ * gateway is encoded as RTA_VIA
+ */
+ if (nhc->nhc_gw_family != nhc->nhc_family) {
+ int alen = sizeof(struct in6_addr);
+ struct nlattr *nla;
+ struct rtvia *via;
+
+ nla = nla_reserve(skb, RTA_VIA, alen + 2);
+ if (!nla)
+ goto nla_put_failure;
+
+ via = nla_data(nla);
+ via->rtvia_family = AF_INET6;
+ memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
+ } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
+ &nhc->nhc_gw.ipv6) < 0) {
goto nla_put_failure;
+ }
break;
}
--
2.11.0
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