net: mpls: Add extack messages for route add and delete failures

Add error messages for failures in adding and deleting mpls routes.
This covers most of the annoying EINVAL errors.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 726eafe..0133d1a 100644 (file)
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -720,7 +720,8 @@ errout:
 
 static int mpls_nh_build(struct net *net, struct mpls_route *rt,
                         struct mpls_nh *nh, int oif, struct nlattr *via,
-                        struct nlattr *newdst, u8 max_labels)
+                        struct nlattr *newdst, u8 max_labels,
+                        struct netlink_ext_ack *extack)
 {
        int err = -ENOMEM;
 
@@ -729,14 +730,14 @@ static int mpls_nh_build(struct net *net, struct mpls_route *rt,
 
        if (newdst) {
                err = nla_get_labels(newdst, max_labels, &nh->nh_labels,
-                                    nh->nh_label, NULL);
+                                    nh->nh_label, extack);
                if (err)
                        goto errout;
        }
 
        if (via) {
                err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
-                                 __mpls_nh_via(rt, nh));
+                                 __mpls_nh_via(rt, nh), extack);
                if (err)
                        goto errout;
        } else {
@@ -803,7 +804,8 @@ static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len,
 }
 
 static int mpls_nh_build_multi(struct mpls_route_config *cfg,
-                              struct mpls_route *rt, u8 max_labels)
+                              struct mpls_route *rt, u8 max_labels,
+                              struct netlink_ext_ack *extack)
 {
        struct rtnexthop *rtnh = cfg->rc_mp;
        struct nlattr *nla_via, *nla_newdst;
@@ -837,7 +839,7 @@ static int mpls_nh_build_multi(struct mpls_route_config *cfg,
 
                err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh,
                                    rtnh->rtnh_ifindex, nla_via, nla_newdst,
-                                   max_labels);
+                                   max_labels, extack);
                if (err)
                        goto errout;
 
@@ -856,20 +858,28 @@ errout:
        return err;
 }
 
-static bool mpls_label_ok(struct net *net, unsigned int index)
+static bool mpls_label_ok(struct net *net, unsigned int index,
+                         struct netlink_ext_ack *extack)
 {
        /* Reserved labels may not be set */
-       if (index < MPLS_LABEL_FIRST_UNRESERVED)
+       if (index < MPLS_LABEL_FIRST_UNRESERVED) {
+               NL_SET_ERR_MSG(extack,
+                              "Invalid label - must be MPLS_LABEL_FIRST_UNRESERVED or higher");
                return false;
+       }
 
        /* The full 20 bit range may not be supported. */
-       if (index >= net->mpls.platform_labels)
+       if (index >= net->mpls.platform_labels) {
+               NL_SET_ERR_MSG(extack,
+                              "Label >= configured maximum in platform_labels");
                return false;
+       }
 
        return true;
 }
 
-static int mpls_route_add(struct mpls_route_config *cfg)
+static int mpls_route_add(struct mpls_route_config *cfg,
+                         struct netlink_ext_ack *extack)
 {
        struct mpls_route __rcu **platform_label;
        struct net *net = cfg->rc_nlinfo.nl_net;
@@ -888,13 +898,15 @@ static int mpls_route_add(struct mpls_route_config *cfg)
                index = find_free_label(net);
        }
 
-       if (!mpls_label_ok(net, index))
+       if (!mpls_label_ok(net, index, extack))
                goto errout;
 
        /* Append makes no sense with mpls */
        err = -EOPNOTSUPP;
-       if (cfg->rc_nlflags & NLM_F_APPEND)
+       if (cfg->rc_nlflags & NLM_F_APPEND) {
+               NL_SET_ERR_MSG(extack, "MPLS does not support route append");
                goto errout;
+       }
 
        err = -EEXIST;
        platform_label = rtnl_dereference(net->mpls.platform_label);
@@ -921,8 +933,10 @@ static int mpls_route_add(struct mpls_route_config *cfg)
                nhs = 1;
        }
 
-       if (nhs == 0)
+       if (nhs == 0) {
+               NL_SET_ERR_MSG(extack, "Route does not contain a nexthop");
                goto errout;
+       }
 
        err = -ENOMEM;
        rt = mpls_rt_alloc(nhs, max_via_alen, max_labels);
@@ -936,7 +950,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
        rt->rt_ttl_propagate = cfg->rc_ttl_propagate;
 
        if (cfg->rc_mp)
-               err = mpls_nh_build_multi(cfg, rt, max_labels);
+               err = mpls_nh_build_multi(cfg, rt, max_labels, extack);
        else
                err = mpls_nh_build_from_cfg(cfg, rt);
        if (err)
@@ -952,7 +966,8 @@ errout:
        return err;
 }
 
-static int mpls_route_del(struct mpls_route_config *cfg)
+static int mpls_route_del(struct mpls_route_config *cfg,
+                         struct netlink_ext_ack *extack)
 {
        struct net *net = cfg->rc_nlinfo.nl_net;
        unsigned index;
@@ -960,7 +975,7 @@ static int mpls_route_del(struct mpls_route_config *cfg)
 
        index = cfg->rc_label;
 
-       if (!mpls_label_ok(net, index))
+       if (!mpls_label_ok(net, index, extack))
                goto errout;
 
        mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
@@ -1626,19 +1641,25 @@ out:
 }
 EXPORT_SYMBOL_GPL(nla_get_labels);
 
-int nla_get_via(const struct nlattr *nla, u8 *via_alen,
-               u8 *via_table, u8 via_addr[])
+int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
+               u8 via_addr[], struct netlink_ext_ack *extack)
 {
        struct rtvia *via = nla_data(nla);
        int err = -EINVAL;
        int alen;
 
-       if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
+       if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
+               NL_SET_ERR_MSG_ATTR(extack, nla,
+                                   "Invalid attribute length for RTA_VIA");
                goto errout;
+       }
        alen = nla_len(nla) -
                        offsetof(struct rtvia, rtvia_addr);
-       if (alen > MAX_VIA_ALEN)
+       if (alen > MAX_VIA_ALEN) {
+               NL_SET_ERR_MSG_ATTR(extack, nla,
+                                   "Invalid address length for RTA_VIA");
                goto errout;
+       }
 
        /* Validate the address family */
        switch (via->rtvia_family) {
@@ -1668,8 +1689,10 @@ errout:
        return err;
 }
 
-static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
-                              struct mpls_route_config *cfg)
+static int rtm_to_route_config(struct sk_buff *skb,
+                              struct nlmsghdr *nlh,
+                              struct mpls_route_config *cfg,
+                              struct netlink_ext_ack *extack)
 {
        struct rtmsg *rtm;
        struct nlattr *tb[RTA_MAX+1];
@@ -1677,35 +1700,54 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
        int err;
 
        err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_mpls_policy,
-                         NULL);
+                         extack);
        if (err < 0)
                goto errout;
 
        err = -EINVAL;
        rtm = nlmsg_data(nlh);
 
-       if (rtm->rtm_family != AF_MPLS)
+       if (rtm->rtm_family != AF_MPLS) {
+               NL_SET_ERR_MSG(extack, "Invalid address family in rtmsg");
                goto errout;
-       if (rtm->rtm_dst_len != 20)
+       }
+       if (rtm->rtm_dst_len != 20) {
+               NL_SET_ERR_MSG(extack, "rtm_dst_len must be 20 for MPLS");
                goto errout;
-       if (rtm->rtm_src_len != 0)
+       }
+       if (rtm->rtm_src_len != 0) {
+               NL_SET_ERR_MSG(extack, "rtm_src_len must be 0 for MPLS");
                goto errout;
-       if (rtm->rtm_tos != 0)
+       }
+       if (rtm->rtm_tos != 0) {
+               NL_SET_ERR_MSG(extack, "rtm_tos must be 0 for MPLS");
                goto errout;
-       if (rtm->rtm_table != RT_TABLE_MAIN)
+       }
+       if (rtm->rtm_table != RT_TABLE_MAIN) {
+               NL_SET_ERR_MSG(extack,
+                              "MPLS only supports the main route table");
                goto errout;
+       }
        /* Any value is acceptable for rtm_protocol */
 
        /* As mpls uses destination specific addresses
         * (or source specific address in the case of multicast)
         * all addresses have universal scope.
         */
-       if (rtm->rtm_scope != RT_SCOPE_UNIVERSE)
+       if (rtm->rtm_scope != RT_SCOPE_UNIVERSE) {
+               NL_SET_ERR_MSG(extack,
+                              "Invalid route scope  - MPLS only supports UNIVERSE");
                goto errout;
-       if (rtm->rtm_type != RTN_UNICAST)
+       }
+       if (rtm->rtm_type != RTN_UNICAST) {
+               NL_SET_ERR_MSG(extack,
+                              "Invalid route type - MPLS only supports UNICAST");
                goto errout;
-       if (rtm->rtm_flags != 0)
+       }
+       if (rtm->rtm_flags != 0) {
+               NL_SET_ERR_MSG(extack, "rtm_flags must be 0 for MPLS");
                goto errout;
+       }
 
        cfg->rc_label           = LABEL_NOT_SPECIFIED;
        cfg->rc_protocol        = rtm->rtm_protocol;
@@ -1728,25 +1770,26 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
                case RTA_NEWDST:
                        if (nla_get_labels(nla, MAX_NEW_LABELS,
                                           &cfg->rc_output_labels,
-                                          cfg->rc_output_label, NULL))
+                                          cfg->rc_output_label, extack))
                                goto errout;
                        break;
                case RTA_DST:
                {
                        u8 label_count;
                        if (nla_get_labels(nla, 1, &label_count,
-                                          &cfg->rc_label, NULL))
+                                          &cfg->rc_label, extack))
                                goto errout;
 
                        if (!mpls_label_ok(cfg->rc_nlinfo.nl_net,
-                                          cfg->rc_label))
+                                          cfg->rc_label, extack))
                                goto errout;
                        break;
                }
                case RTA_VIA:
                {
                        if (nla_get_via(nla, &cfg->rc_via_alen,
-                                       &cfg->rc_via_table, cfg->rc_via))
+                                       &cfg->rc_via_table, cfg->rc_via,
+                                       extack))
                                goto errout;
                        break;
                }
@@ -1760,14 +1803,18 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
                {
                        u8 ttl_propagate = nla_get_u8(nla);
 
-                       if (ttl_propagate > 1)
+                       if (ttl_propagate > 1) {
+                               NL_SET_ERR_MSG_ATTR(extack, nla,
+                                                   "RTA_TTL_PROPAGATE can only be 0 or 1");
                                goto errout;
+                       }
                        cfg->rc_ttl_propagate = ttl_propagate ?
                                MPLS_TTL_PROP_ENABLED :
                                MPLS_TTL_PROP_DISABLED;
                        break;
                }
                default:
+                       NL_SET_ERR_MSG_ATTR(extack, nla, "Unknown attribute");
                        /* Unsupported attribute */
                        goto errout;
                }
@@ -1788,11 +1835,11 @@ static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (!cfg)
                return -ENOMEM;
 
-       err = rtm_to_route_config(skb, nlh, cfg);
+       err = rtm_to_route_config(skb, nlh, cfg, extack);
        if (err < 0)
                goto out;
 
-       err = mpls_route_del(cfg);
+       err = mpls_route_del(cfg, extack);
 out:
        kfree(cfg);
 
@@ -1810,11 +1857,11 @@ static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (!cfg)
                return -ENOMEM;
 
-       err = rtm_to_route_config(skb, nlh, cfg);
+       err = rtm_to_route_config(skb, nlh, cfg, extack);
        if (err < 0)
                goto out;
 
-       err = mpls_route_add(cfg);
+       err = mpls_route_add(cfg, extack);
 out:
        kfree(cfg);
 

diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index e59f299..a015a6a 100644 (file)
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -205,7 +205,7 @@ int nla_put_labels(struct sk_buff *skb, int attrtype,  u8 labels,
 int nla_get_labels(const struct nlattr *nla, u8 max_labels, u8 *labels,
                   u32 label[], struct netlink_ext_ack *extack);
 int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
-               u8 via[]);
+               u8 via[], struct netlink_ext_ack *extack);
 bool mpls_output_possible(const struct net_device *dev);
 unsigned int mpls_dev_mtu(const struct net_device *dev);
 bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu);