geneve: use netlink_ext_ack for error reporting in rtnl operations

Add extack error messages for failure paths while creating/modifying
geneve devices. Once extack support is added to iproute2, more
meaningful and helpful error messages will be displayed making it easy
for users to discern what went wrong.

Before:

=======
$ ip link add gen1 address 0:1:2:3:4:5:6 type geneve id 200 \
  remote 192.168.13.2
RTNETLINK answers: Invalid argument

After:
======
$ ip link add gen1 address 0:1:2:3:4:5:6 type geneve id 200 \
  remote 192.168.13.2
Error: Provided link layer address is not Ethernet

Also, netdev_dbg() calls used to log errors associated with Netlink
request have been removed.

Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 92 insertions, 36 deletions

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 8b8565dd2afb..f6404074b7b0 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1086,21 +1086,33 @@ static int geneve_validate(struct nlattr *tb[], struct nlattr *data[],
                            struct netlink_ext_ack *extack)
 {
         if (tb[IFLA_ADDRESS]) {
-                if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
+                if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) {
+                        NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_ADDRESS],
+                                            "Provided link layer address is not Ethernet");
                         return -EINVAL;
+                }
 
-                if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
+                if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) {
+                        NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_ADDRESS],
+                                            "Provided Ethernet address is not unicast");
                         return -EADDRNOTAVAIL;
+                }
         }
 
-        if (!data)
+        if (!data) {
+                NL_SET_ERR_MSG(extack,
+                               "Not enough attributes provided to perform the operation");
                 return -EINVAL;
+        }
 
         if (data[IFLA_GENEVE_ID]) {
                 __u32 vni =  nla_get_u32(data[IFLA_GENEVE_ID]);
 
-                if (vni >= GENEVE_N_VID)
+                if (vni >= GENEVE_N_VID) {
+                        NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_ID],
+                                            "Geneve ID must be lower than 16777216");
                         return -ERANGE;
+                }
         }
 
         return 0;
@@ -1158,6 +1170,7 @@ static bool geneve_dst_addr_equal(struct ip_tunnel_info *a,
 }
 
 static int geneve_configure(struct net *net, struct net_device *dev,
+                            struct netlink_ext_ack *extack,
                             const struct ip_tunnel_info *info,
                             bool metadata, bool ipv6_rx_csum)
 {
@@ -1166,8 +1179,11 @@ static int geneve_configure(struct net *net, struct net_device *dev,
         bool tun_collect_md, tun_on_same_port;
         int err, encap_len;
 
-        if (metadata && !is_tnl_info_zero(info))
+        if (metadata && !is_tnl_info_zero(info)) {
+                NL_SET_ERR_MSG(extack,
+                               "Device is externally controlled, so attributes (VNI, Port, and so on) must not be specified");
                 return -EINVAL;
+        }
 
         geneve->net = net;
         geneve->dev = dev;
@@ -1188,11 +1204,17 @@ static int geneve_configure(struct net *net, struct net_device *dev,
         dev->needed_headroom = encap_len + ETH_HLEN;
 
         if (metadata) {
-                if (tun_on_same_port)
+                if (tun_on_same_port) {
+                        NL_SET_ERR_MSG(extack,
+                                       "There can be only one externally controlled device on a destination port");
                         return -EPERM;
+                }
         } else {
-                if (tun_collect_md)
+                if (tun_collect_md) {
+                        NL_SET_ERR_MSG(extack,
+                                       "There already exists an externally controlled device on this destination port");
                         return -EPERM;
+                }
         }
 
         dst_cache_reset(&geneve->info.dst_cache);
@@ -1214,31 +1236,41 @@ static void init_tnl_info(struct ip_tunnel_info *info, __u16 dst_port)
         info->key.tp_dst = htons(dst_port);
 }
 
-static int geneve_nl2info(struct net_device *dev, struct nlattr *tb[],
-                          struct nlattr *data[], struct ip_tunnel_info *info,
-                          bool *metadata, bool *use_udp6_rx_checksums,
-                          bool changelink)
+static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
+                          struct netlink_ext_ack *extack,
+                          struct ip_tunnel_info *info, bool *metadata,
+                          bool *use_udp6_rx_checksums, bool changelink)
 {
-        if (data[IFLA_GENEVE_REMOTE] && data[IFLA_GENEVE_REMOTE6])
+        int attrtype;
+
+        if (data[IFLA_GENEVE_REMOTE] && data[IFLA_GENEVE_REMOTE6]) {
+                NL_SET_ERR_MSG(extack,
+                               "Cannot specify both IPv4 and IPv6 Remote addresses");
                 return -EINVAL;
+        }
 
         if (data[IFLA_GENEVE_REMOTE]) {
-                if (changelink && (ip_tunnel_info_af(info) == AF_INET6))
-                        return -EOPNOTSUPP;
+                if (changelink && (ip_tunnel_info_af(info) == AF_INET6)) {
+                        attrtype = IFLA_GENEVE_REMOTE;
+                        goto change_notsup;
+                }
 
                 info->key.u.ipv4.dst =
                         nla_get_in_addr(data[IFLA_GENEVE_REMOTE]);
 
                 if (IN_MULTICAST(ntohl(info->key.u.ipv4.dst))) {
-                        netdev_dbg(dev, "multicast remote is unsupported\n");
+                        NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE],
+                                            "Remote IPv4 address cannot be Multicast");
                         return -EINVAL;
                 }
         }
 
         if (data[IFLA_GENEVE_REMOTE6]) {
  #if IS_ENABLED(CONFIG_IPV6)
-                if (changelink && (ip_tunnel_info_af(info) == AF_INET))
-                        return -EOPNOTSUPP;
+                if (changelink && (ip_tunnel_info_af(info) == AF_INET)) {
+                        attrtype = IFLA_GENEVE_REMOTE6;
+                        goto change_notsup;
+                }
 
                 info->mode = IP_TUNNEL_INFO_IPV6;
                 info->key.u.ipv6.dst =
@@ -1246,16 +1278,20 @@ static int geneve_nl2info(struct net_device *dev, struct nlattr *tb[],
 
                 if (ipv6_addr_type(&info->key.u.ipv6.dst) &
                     IPV6_ADDR_LINKLOCAL) {
-                        netdev_dbg(dev, "link-local remote is unsupported\n");
+                        NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE6],
+                                            "Remote IPv6 address cannot be link-local");
                         return -EINVAL;
                 }
                 if (ipv6_addr_is_multicast(&info->key.u.ipv6.dst)) {
-                        netdev_dbg(dev, "multicast remote is unsupported\n");
+                        NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE6],
+                                            "Remote IPv6 address cannot be Multicast");
                         return -EINVAL;
                 }
                 info->key.tun_flags |= TUNNEL_CSUM;
                 *use_udp6_rx_checksums = true;
 #else
+                NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE6],
+                                    "IPv6 support not enabled in the kernel");
                 return -EPFNOSUPPORT;
 #endif
         }
@@ -1271,8 +1307,10 @@ static int geneve_nl2info(struct net_device *dev, struct nlattr *tb[],
                 tvni[2] =  vni & 0x000000ff;
 
                 tunid = vni_to_tunnel_id(tvni);
-                if (changelink && (tunid != info->key.tun_id))
-                        return -EOPNOTSUPP;
+                if (changelink && (tunid != info->key.tun_id)) {
+                        attrtype = IFLA_GENEVE_ID;
+                        goto change_notsup;
+                }
                 info->key.tun_id = tunid;
         }
 
@@ -1285,44 +1323,61 @@ static int geneve_nl2info(struct net_device *dev, struct nlattr *tb[],
         if (data[IFLA_GENEVE_LABEL]) {
                 info->key.label = nla_get_be32(data[IFLA_GENEVE_LABEL]) &
                                   IPV6_FLOWLABEL_MASK;
-                if (info->key.label && (!(info->mode & IP_TUNNEL_INFO_IPV6)))
+                if (info->key.label && (!(info->mode & IP_TUNNEL_INFO_IPV6))) {
+                        NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_LABEL],
+                                            "Label attribute only applies for IPv6 Geneve devices");
                         return -EINVAL;
+                }
         }
 
         if (data[IFLA_GENEVE_PORT]) {
-                if (changelink)
-                        return -EOPNOTSUPP;
+                if (changelink) {
+                        attrtype = IFLA_GENEVE_PORT;
+                        goto change_notsup;
+                }
                 info->key.tp_dst = nla_get_be16(data[IFLA_GENEVE_PORT]);
         }
 
         if (data[IFLA_GENEVE_COLLECT_METADATA]) {
-                if (changelink)
-                        return -EOPNOTSUPP;
+                if (changelink) {
+                        attrtype = IFLA_GENEVE_COLLECT_METADATA;
+                        goto change_notsup;
+                }
                 *metadata = true;
         }
 
         if (data[IFLA_GENEVE_UDP_CSUM]) {
-                if (changelink)
-                        return -EOPNOTSUPP;
+                if (changelink) {
+                        attrtype = IFLA_GENEVE_UDP_CSUM;
+                        goto change_notsup;
+                }
                 if (nla_get_u8(data[IFLA_GENEVE_UDP_CSUM]))
                         info->key.tun_flags |= TUNNEL_CSUM;
         }
 
         if (data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]) {
-                if (changelink)
-                        return -EOPNOTSUPP;
+                if (changelink) {
+                        attrtype = IFLA_GENEVE_UDP_ZERO_CSUM6_TX;
+                        goto change_notsup;
+                }
                 if (nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]))
                         info->key.tun_flags &= ~TUNNEL_CSUM;
         }
 
         if (data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]) {
-                if (changelink)
-                        return -EOPNOTSUPP;
+                if (changelink) {
+                        attrtype = IFLA_GENEVE_UDP_ZERO_CSUM6_RX;
+                        goto change_notsup;
+                }
                 if (nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]))
                         *use_udp6_rx_checksums = false;
         }
 
         return 0;
+change_notsup:
+        NL_SET_ERR_MSG_ATTR(extack, data[attrtype],
+                            "Changing VNI, Port, endpoint IP address family, external, and UDP checksum attributes are not supported");
+        return -EOPNOTSUPP;
 }
 
 static int geneve_newlink(struct net *net, struct net_device *dev,
@@ -1335,12 +1390,13 @@ static int geneve_newlink(struct net *net, struct net_device *dev,
         int err;
 
         init_tnl_info(&info, GENEVE_UDP_PORT);
-        err = geneve_nl2info(dev, tb, data, &info, &metadata,
+        err = geneve_nl2info(tb, data, extack, &info, &metadata,
                              &use_udp6_rx_checksums, false);
         if (err)
                 return err;
 
-        return geneve_configure(net, dev, &info, metadata, use_udp6_rx_checksums);
+        return geneve_configure(net, dev, extack, &info, metadata,
+                                use_udp6_rx_checksums);
 }
 
 /* Quiesces the geneve device data path for both TX and RX.
@@ -1409,7 +1465,7 @@ static int geneve_changelink(struct net_device *dev, struct nlattr *tb[],
         memcpy(&info, &geneve->info, sizeof(info));
         metadata = geneve->collect_md;
         use_udp6_rx_checksums = geneve->use_udp6_rx_checksums;
-        err = geneve_nl2info(dev, tb, data, &info, &metadata,
+        err = geneve_nl2info(tb, data, extack, &info, &metadata,
                              &use_udp6_rx_checksums, true);
         if (err)
                 return err;
@@ -1536,7 +1592,7 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name,
                 return dev;
 
         init_tnl_info(&info, dst_port);
-        err = geneve_configure(net, dev, &info, true, true);
+        err = geneve_configure(net, dev, NULL, &info, true, true);
         if (err) {
                 free_netdev(dev);
                 return ERR_PTR(err);