ipv6: Add flow label to route get requests

The default IPv6 multipath hash policy takes the flow label into account
when calculating a multipath hash and previous patches added a flow
label selector to IPv6 FIB rules.

Allow user space to specify a flow label in route get requests by adding
a new netlink attribute and using its value to populate the "flowlabel"
field in the IPv6 flow info structure prior to a route lookup.

Deny the attribute in RTM_{NEW,DEL}ROUTE requests by checking for it in
rtm_to_fib6_config() and returning an error if present.

A subsequent patch will use this capability to test the new flow label
selector in IPv6 FIB rules.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index eccc0e7dcb7dbc4382fcebb9f4bc444d9792b2fa..5ee94c511a28a9312d9ac6573cdd7c9b649d22c7 100644 (file)
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -393,6 +393,7 @@ enum rtattr_type_t {
        RTA_SPORT,
        RTA_DPORT,
        RTA_NH_ID,
+       RTA_FLOWLABEL,
        __RTA_MAX
 };
 

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 67ff16c047180bfb3928d16226f5bf864e2361fb..78362822b9070df138a0724dc76003b63026f9e2 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -5005,6 +5005,7 @@ static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
        [RTA_SPORT]             = { .type = NLA_U16 },
        [RTA_DPORT]             = { .type = NLA_U16 },
        [RTA_NH_ID]             = { .type = NLA_U32 },
+       [RTA_FLOWLABEL]         = { .type = NLA_BE32 },
 };
 
 static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -5030,6 +5031,12 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
                goto errout;
        }
 
+       if (tb[RTA_FLOWLABEL]) {
+               NL_SET_ERR_MSG_ATTR(extack, tb[RTA_FLOWLABEL],
+                                   "Flow label cannot be specified for this operation");
+               goto errout;
+       }
+
        *cfg = (struct fib6_config){
                .fc_table = rtm->rtm_table,
                .fc_dst_len = rtm->rtm_dst_len,
@@ -6013,6 +6020,13 @@ static int inet6_rtm_valid_getroute_req(struct sk_buff *skb,
                return -EINVAL;
        }
 
+       if (tb[RTA_FLOWLABEL] &&
+           (nla_get_be32(tb[RTA_FLOWLABEL]) & ~IPV6_FLOWLABEL_MASK)) {
+               NL_SET_ERR_MSG_ATTR(extack, tb[RTA_FLOWLABEL],
+                                   "Invalid flow label");
+               return -EINVAL;
+       }
+
        for (i = 0; i <= RTA_MAX; i++) {
                if (!tb[i])
                        continue;
@@ -6027,6 +6041,7 @@ static int inet6_rtm_valid_getroute_req(struct sk_buff *skb,
                case RTA_SPORT:
                case RTA_DPORT:
                case RTA_IP_PROTO:
+               case RTA_FLOWLABEL:
                        break;
                default:
                        NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in get route request");
@@ -6049,6 +6064,7 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
        struct sk_buff *skb;
        struct rtmsg *rtm;
        struct flowi6 fl6 = {};
+       __be32 flowlabel;
        bool fibmatch;
 
        err = inet6_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
@@ -6057,7 +6073,6 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 
        err = -EINVAL;
        rtm = nlmsg_data(nlh);
-       fl6.flowlabel = ip6_make_flowinfo(rtm->rtm_tos, 0);
        fibmatch = !!(rtm->rtm_flags & RTM_F_FIB_MATCH);
 
        if (tb[RTA_SRC]) {
@@ -6103,6 +6118,9 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
                        goto errout;
        }
 
+       flowlabel = nla_get_be32_default(tb[RTA_FLOWLABEL], 0);
+       fl6.flowlabel = ip6_make_flowinfo(rtm->rtm_tos, flowlabel);
+
        if (iif) {
                struct net_device *dev;
                int flags = 0;