genetlink: no longer support using static family IDs

Static family IDs have never really been used, the only
use case was the workaround I introduced for those users
that assumed their family ID was also their multicast
group ID.

Additionally, because static family IDs would never be
reserved by the generic netlink code, using a relatively
low ID would only work for built-in families that can be
registered immediately after generic netlink is started,
which is basically only the control family (apart from
the workaround code, which I also had to add code for so
it would reserve those IDs)

Thus, anything other than GENL_ID_GENERATE is flawed and
luckily not used except in the cases I mentioned. Move
those workarounds into a few lines of code, and then get
rid of GENL_ID_GENERATE entirely, making it more robust.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

23 files changed, 22 insertions, 40 deletions

diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index 64cb6acbe0a6..a03b0ed7e8dd 100644
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -49,7 +49,6 @@
 #include "translation-table.h"
 
 struct genl_family batadv_netlink_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = 0,
         .name = BATADV_NL_NAME,
         .version = 1,
diff --git a/net/core/devlink.c b/net/core/devlink.c
index d2fd736de6a2..3008d9c33875 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -342,7 +342,6 @@ static void devlink_nl_post_doit(const struct genl_ops *ops,
 }
 
 static struct genl_family devlink_nl_family = {
-        .id             = GENL_ID_GENERATE,
         .name           = DEVLINK_GENL_NAME,
         .version        = DEVLINK_GENL_VERSION,
         .maxattr        = DEVLINK_ATTR_MAX,
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 72cfb0c61125..a5320dfcd978 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -60,7 +60,6 @@ struct dm_hw_stat_delta {
 };
 
 static struct genl_family net_drop_monitor_family = {
-        .id             = GENL_ID_GENERATE,
         .hdrsize        = 0,
         .name           = "NET_DM",
         .version        = 2,
diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
index d4d1617f43a8..2ad039492bee 100644
--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -132,7 +132,6 @@ static const struct nla_policy hsr_genl_policy[HSR_A_MAX + 1] = {
 };
 
 static struct genl_family hsr_genl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = 0,
         .name = "HSR",
         .version = 1,
diff --git a/net/ieee802154/netlink.c b/net/ieee802154/netlink.c
index c8133c07ceee..19144158b696 100644
--- a/net/ieee802154/netlink.c
+++ b/net/ieee802154/netlink.c
@@ -29,7 +29,6 @@ static unsigned int ieee802154_seq_num;
 static DEFINE_SPINLOCK(ieee802154_seq_lock);
 
 struct genl_family nl802154_family = {
-        .id             = GENL_ID_GENERATE,
         .hdrsize        = 0,
         .name           = IEEE802154_NL_NAME,
         .version        = 1,
diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 21aabadccd0e..182299858f1d 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -34,7 +34,6 @@ static void nl802154_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
 
 /* the netlink family */
 static struct genl_family nl802154_fam = {
-        .id = GENL_ID_GENERATE,         /* don't bother with a hardcoded ID */
         .name = NL802154_GENL_NAME,     /* have users key off the name instead */
         .hdrsize = 0,                   /* no private header */
         .version = 1,                   /* no particular meaning now */
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index cf50f7e2b012..e3fc527c5d37 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -623,7 +623,6 @@ static int fou_destroy(struct net *net, struct fou_cfg *cfg)
 }
 
 static struct genl_family fou_nl_family = {
-        .id             = GENL_ID_GENERATE,
         .hdrsize        = 0,
         .name           = FOU_GENL_NAME,
         .version        = FOU_GENL_VERSION,
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index bf1f3b2b29d1..3da305127b32 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -743,7 +743,6 @@ void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
 }
 
 static struct genl_family tcp_metrics_nl_family = {
-        .id             = GENL_ID_GENERATE,
         .hdrsize        = 0,
         .name           = TCP_METRICS_GENL_NAME,
         .version        = TCP_METRICS_GENL_VERSION,
diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index e604013dd814..0d57e27d1cdd 100644
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -119,7 +119,6 @@ static const struct rhashtable_params rht_params = {
 };
 
 static struct genl_family ila_nl_family = {
-        .id             = GENL_ID_GENERATE,
         .hdrsize        = 0,
         .name           = ILA_GENL_NAME,
         .version        = ILA_GENL_VERSION,
diff --git a/net/irda/irnetlink.c b/net/irda/irnetlink.c
index e15c40e86660..f23b81aa91fe 100644
--- a/net/irda/irnetlink.c
+++ b/net/irda/irnetlink.c
@@ -25,7 +25,6 @@
 
 
 static struct genl_family irda_nl_family = {
-        .id = GENL_ID_GENERATE,
         .name = IRDA_NL_NAME,
         .hdrsize = 0,
         .version = IRDA_NL_VERSION,
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index bf3117771822..4fbf1f41ac52 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -32,7 +32,6 @@
 
 
 static struct genl_family l2tp_nl_family = {
-        .id             = GENL_ID_GENERATE,
         .name           = L2TP_GENL_NAME,
         .version        = L2TP_GENL_VERSION,
         .hdrsize        = 0,
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index c3c809b2e712..ceed66cdd03e 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2841,7 +2841,6 @@ static struct nf_sockopt_ops ip_vs_sockopts = {
 
 /* IPVS genetlink family */
 static struct genl_family ip_vs_genl_family = {
-        .id             = GENL_ID_GENERATE,
         .hdrsize        = 0,
         .name           = IPVS_GENL_NAME,
         .version        = IPVS_GENL_VERSION,
diff --git a/net/netlabel/netlabel_calipso.c b/net/netlabel/netlabel_calipso.c
index 2ec93c5e77bb..152e503b8c5d 100644
--- a/net/netlabel/netlabel_calipso.c
+++ b/net/netlabel/netlabel_calipso.c
@@ -61,7 +61,6 @@ struct netlbl_domhsh_walk_arg {
 
 /* NetLabel Generic NETLINK CALIPSO family */
 static struct genl_family netlbl_calipso_gnl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = 0,
         .name = NETLBL_NLTYPE_CALIPSO_NAME,
         .version = NETLBL_PROTO_VERSION,
diff --git a/net/netlabel/netlabel_cipso_v4.c b/net/netlabel/netlabel_cipso_v4.c
index 7fd1104ba900..755b284e7ad4 100644
--- a/net/netlabel/netlabel_cipso_v4.c
+++ b/net/netlabel/netlabel_cipso_v4.c
@@ -60,7 +60,6 @@ struct netlbl_domhsh_walk_arg {
 
 /* NetLabel Generic NETLINK CIPSOv4 family */
 static struct genl_family netlbl_cipsov4_gnl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = 0,
         .name = NETLBL_NLTYPE_CIPSOV4_NAME,
         .version = NETLBL_PROTO_VERSION,
diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index f85d0e07af2d..3b00f2368fcd 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c
@@ -61,7 +61,6 @@ struct netlbl_domhsh_walk_arg {
 
 /* NetLabel Generic NETLINK CIPSOv4 family */
 static struct genl_family netlbl_mgmt_gnl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = 0,
         .name = NETLBL_NLTYPE_MGMT_NAME,
         .version = NETLBL_PROTO_VERSION,
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 4528cff9138b..c2ea8d1f653a 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -124,7 +124,6 @@ static u8 netlabel_unlabel_acceptflg;
 
 /* NetLabel Generic NETLINK unlabeled family */
 static struct genl_family netlbl_unlabel_gnl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = 0,
         .name = NETLBL_NLTYPE_UNLABELED_NAME,
         .version = NETLBL_PROTO_VERSION,
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 01291b7a27bb..f19ec969edee 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -349,8 +349,6 @@ static int genl_validate_ops(const struct genl_family *family)
  *
  * Registers the specified family after validating it first. Only one
  * family may be registered with the same family name or identifier.
- * The family id may equal GENL_ID_GENERATE causing an unique id to
- * be automatically generated and assigned.
  *
  * The family's ops array must already be assigned, you can use the
  * genl_register_family_with_ops() helper function.
@@ -359,13 +357,7 @@ static int genl_validate_ops(const struct genl_family *family)
  */
 int __genl_register_family(struct genl_family *family)
 {
-        int err = -EINVAL, i;
-
-        if (family->id && family->id < GENL_MIN_ID)
-                goto errout;
-
-        if (family->id > GENL_MAX_ID)
-                goto errout;
+        int err, i;
 
         err = genl_validate_ops(family);
         if (err)
@@ -378,8 +370,27 @@ int __genl_register_family(struct genl_family *family)
                 goto errout_locked;
         }
 
-        if (family->id == GENL_ID_GENERATE) {
-                u16 newid = genl_generate_id();
+        if (family == &genl_ctrl) {
+                family->id = GENL_ID_CTRL;
+        } else {
+                u16 newid;
+
+                /* this should be left zero in the struct */
+                WARN_ON(family->id);
+
+                /*
+                 * Sadly, a few cases need to be special-cased
+                 * due to them having previously abused the API
+                 * and having used their family ID also as their
+                 * multicast group ID, so we use reserved IDs
+                 * for both to be sure we can do that mapping.
+                 */
+                if (strcmp(family->name, "pmcraid") == 0)
+                        newid = GENL_ID_PMCRAID;
+                else if (strcmp(family->name, "VFS_DQUOT") == 0)
+                        newid = GENL_ID_VFS_DQUOT;
+                else
+                        newid = genl_generate_id();
 
                 if (!newid) {
                         err = -ENOMEM;
@@ -387,9 +398,6 @@ int __genl_register_family(struct genl_family *family)
                 }
 
                 family->id = newid;
-        } else if (genl_family_find_byid(family->id)) {
-                err = -EEXIST;
-                goto errout_locked;
         }
 
         if (family->maxattr && !family->parallel_ops) {
@@ -419,7 +427,6 @@ int __genl_register_family(struct genl_family *family)
 
 errout_locked:
         genl_unlock_all();
-errout:
         return err;
 }
 EXPORT_SYMBOL(__genl_register_family);
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 79786bf62b88..c230403e066c 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -39,7 +39,6 @@ static const struct genl_multicast_group nfc_genl_mcgrps[] = {
 };
 
 static struct genl_family nfc_genl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = 0,
         .name = NFC_GENL_NAME,
         .version = NFC_GENL_VERSION,
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 194435aa1165..f9fef7dfba15 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -671,7 +671,6 @@ static const struct genl_ops dp_packet_genl_ops[] = {
 };
 
 static struct genl_family dp_packet_genl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = sizeof(struct ovs_header),
         .name = OVS_PACKET_FAMILY,
         .version = OVS_PACKET_VERSION,
@@ -1436,7 +1435,6 @@ static const struct genl_ops dp_flow_genl_ops[] = {
 };
 
 static struct genl_family dp_flow_genl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = sizeof(struct ovs_header),
         .name = OVS_FLOW_FAMILY,
         .version = OVS_FLOW_VERSION,
@@ -1822,7 +1820,6 @@ static const struct genl_ops dp_datapath_genl_ops[] = {
 };
 
 static struct genl_family dp_datapath_genl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = sizeof(struct ovs_header),
         .name = OVS_DATAPATH_FAMILY,
         .version = OVS_DATAPATH_VERSION,
@@ -2244,7 +2241,6 @@ static const struct genl_ops dp_vport_genl_ops[] = {
 };
 
 struct genl_family dp_vport_genl_family = {
-        .id = GENL_ID_GENERATE,
         .hdrsize = sizeof(struct ovs_header),
         .name = OVS_VPORT_FAMILY,
         .version = OVS_VPORT_VERSION,
diff --git a/net/tipc/netlink.c b/net/tipc/netlink.c
index 4b94f3cfe3af..383b8fedabc7 100644
--- a/net/tipc/netlink.c
+++ b/net/tipc/netlink.c
@@ -136,7 +136,6 @@ const struct nla_policy tipc_nl_udp_policy[TIPC_NLA_UDP_MAX + 1] = {
  * so we have a separate genl handling for the new API.
  */
 struct genl_family tipc_genl_family = {
-        .id             = GENL_ID_GENERATE,
         .name           = TIPC_GENL_V2_NAME,
         .version        = TIPC_GENL_V2_VERSION,
         .hdrsize        = 0,
diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c
index 1fd464764765..f04428e4c8e5 100644
--- a/net/tipc/netlink_compat.c
+++ b/net/tipc/netlink_compat.c
@@ -1216,7 +1216,6 @@ send:
 }
 
 static struct genl_family tipc_genl_compat_family = {
-        .id             = GENL_ID_GENERATE,
         .name           = TIPC_GENL_NAME,
         .version        = TIPC_GENL_VERSION,
         .hdrsize        = TIPC_GENL_HDRLEN,
diff --git a/net/wimax/stack.c b/net/wimax/stack.c
index 3f816e2971ee..8ac83a41585f 100644
--- a/net/wimax/stack.c
+++ b/net/wimax/stack.c
@@ -573,7 +573,6 @@ size_t D_LEVEL_SIZE = ARRAY_SIZE(D_LEVEL);
 
 
 struct genl_family wimax_gnl_family = {
-        .id = GENL_ID_GENERATE,
         .name = "WiMAX",
         .version = WIMAX_GNL_VERSION,
         .hdrsize = 0,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 7d8cb3330c86..714beafe05e0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -39,7 +39,6 @@ static void nl80211_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
 
 /* the netlink family */
 static struct genl_family nl80211_fam = {
-        .id = GENL_ID_GENERATE,         /* don't bother with a hardcoded ID */
         .name = NL80211_GENL_NAME,      /* have users key off the name instead */
         .hdrsize = 0,                   /* no private header */
         .version = 1,                   /* no particular meaning now */