Commit d1566268 authored by David Ahern's avatar David Ahern Committed by David S. Miller

ipv4: Allow ipv6 gateway with ipv4 routes

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: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 19a9d136
...@@ -401,6 +401,8 @@ static inline bool fib4_rules_early_flow_dissect(struct net *net, ...@@ -401,6 +401,8 @@ static inline bool fib4_rules_early_flow_dissect(struct net *net,
/* Exported by fib_frontend.c */ /* Exported by fib_frontend.c */
extern const struct nla_policy rtm_ipv4_policy[]; extern const struct nla_policy rtm_ipv4_policy[];
void ip_fib_init(void); 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); __be32 fib_compute_spec_dst(struct sk_buff *skb);
bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev); 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, int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
......
...@@ -665,10 +665,55 @@ const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = { ...@@ -665,10 +665,55 @@ const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
[RTA_DPORT] = { .type = NLA_U16 }, [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, static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
struct nlmsghdr *nlh, struct fib_config *cfg, struct nlmsghdr *nlh, struct fib_config *cfg,
struct netlink_ext_ack *extack) struct netlink_ext_ack *extack)
{ {
bool has_gw = false, has_via = false;
struct nlattr *attr; struct nlattr *attr;
int err, remaining; int err, remaining;
struct rtmsg *rtm; struct rtmsg *rtm;
...@@ -709,13 +754,16 @@ static int rtm_to_fib_config(struct net *net, struct sk_buff *skb, ...@@ -709,13 +754,16 @@ static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
cfg->fc_oif = nla_get_u32(attr); cfg->fc_oif = nla_get_u32(attr);
break; break;
case RTA_GATEWAY: case RTA_GATEWAY:
has_gw = true;
cfg->fc_gw_family = AF_INET; cfg->fc_gw_family = AF_INET;
cfg->fc_gw4 = nla_get_be32(attr); cfg->fc_gw4 = nla_get_be32(attr);
break; break;
case RTA_VIA: case RTA_VIA:
NL_SET_ERR_MSG(extack, "IPv4 does not support RTA_VIA attribute"); has_via = true;
err = -EINVAL; err = fib_gw_from_via(cfg, attr, extack);
goto errout; if (err)
goto errout;
break;
case RTA_PRIORITY: case RTA_PRIORITY:
cfg->fc_priority = nla_get_u32(attr); cfg->fc_priority = nla_get_u32(attr);
break; break;
...@@ -754,6 +802,12 @@ static int rtm_to_fib_config(struct net *net, struct sk_buff *skb, ...@@ -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; return 0;
errout: errout:
return err; return err;
......
...@@ -606,12 +606,22 @@ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, ...@@ -606,12 +606,22 @@ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
attrlen = rtnh_attrlen(rtnh); attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) { 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); 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) { if (nla) {
fib_cfg.fc_gw_family = AF_INET; fib_cfg.fc_gw_family = AF_INET;
fib_cfg.fc_gw4 = nla_get_in_addr(nla); 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); nla = nla_find(attrs, attrlen, RTA_FLOW);
...@@ -792,11 +802,43 @@ int fib_nh_match(struct fib_config *cfg, struct fib_info *fi, ...@@ -792,11 +802,43 @@ int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
attrlen = rtnh_attrlen(rtnh); attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) { 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); nla = nla_find(attrs, attrlen, RTA_GATEWAY);
if (nla && nla_get_in_addr(nla) != nh->fib_nh_gw4) nlav = nla_find(attrs, attrlen, RTA_VIA);
return 1; 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 #ifdef CONFIG_IP_ROUTE_CLASSID
nla = nla_find(attrs, attrlen, RTA_FLOW); nla = nla_find(attrs, attrlen, RTA_FLOW);
if (nla && nla_get_u32(nla) != nh->nh_tclassid) 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, ...@@ -1429,8 +1471,25 @@ int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
goto nla_put_failure; goto nla_put_failure;
break; break;
case AF_INET6: 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; goto nla_put_failure;
}
break; break;
} }
......
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