Add a netlink interface to manage the TX TLV parameters. Managed
parameters include those for validating and sending TLVs being sent
such as alignment, TLV ordering, length limits, etc.
---
 include/net/ipv6.h         |  18 +++
 include/uapi/linux/in6.h   |  31 +++++
 net/ipv6/exthdrs_core.c    | 280 +++++++++++++++++++++++++++++++++++++++++++++
 net/ipv6/exthdrs_options.c |  81 ++++++++++++-
 4 files changed, 408 insertions(+), 2 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 9b25d08..a1a0af2 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -17,6 +17,7 @@
 #include <linux/hardirq.h>
 #include <linux/jhash.h>
 #include <linux/refcount.h>
+#include <net/genetlink.h>
 #include <net/if_inet6.h>
 #include <net/ndisc.h>
 #include <net/flow.h>
@@ -449,6 +450,23 @@ int tlv_set_params(struct tlv_param_table *tlv_param_table,
 int tlv_unset_params(struct tlv_param_table *tlv_param_table,
                     unsigned char type);
 
+extern const struct nla_policy tlv_nl_policy[];
+
+int tlv_nl_cmd_set(struct tlv_param_table *tlv_param_table,
+                  struct genl_family *tlv_nl_family,
+                  struct sk_buff *skb, struct genl_info *info);
+int tlv_nl_cmd_unset(struct tlv_param_table *tlv_param_table,
+                    struct genl_family *tlv_nl_family,
+                    struct sk_buff *skb, struct genl_info *info);
+int tlv_nl_cmd_get(struct tlv_param_table *tlv_param_table,
+                  struct genl_family *tlv_nl_family,
+                  struct sk_buff *skb, struct genl_info *info);
+int tlv_fill_info(struct tlv_param_table *tlv_param_table,
+                 int tlv_type, struct sk_buff *msg, bool admin);
+int tlv_nl_dump(struct tlv_param_table *tlv_param_table,
+               struct genl_family *tlv_nl_family,
+               struct sk_buff *skb, struct netlink_callback *cb);
+
 int exthdrs_init(struct tlv_param_table *tlv_param_table,
                 const struct tlv_proc_init *init_params,
                 int num_init_params);
diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h
index 6a99ee1..1c79361 100644
--- a/include/uapi/linux/in6.h
+++ b/include/uapi/linux/in6.h
@@ -306,6 +306,37 @@ struct in6_flowlabel_req {
 
 #define IPV6_TLV_CLASS_ANY_DSTOPT      (IPV6_TLV_CLASS_FLAG_RTRDSTOPT | \
                                        IPV6_TLV_CLASS_FLAG_DSTOPT)
+/* NETLINK_GENERIC related info for IPv6 TLVs */
+
+#define IPV6_TLV_GENL_NAME     "ipv6-tlv"
+#define IPV6_TLV_GENL_VERSION  0x1
+
+enum {
+       IPV6_TLV_ATTR_UNSPEC,
+       IPV6_TLV_ATTR_TYPE,                     /* u8, > 1 */
+       IPV6_TLV_ATTR_ORDER,                    /* u8 */
+       IPV6_TLV_ATTR_ADMIN_PERM,               /* u8, perm value */
+       IPV6_TLV_ATTR_USER_PERM,                /* u8, perm value */
+       IPV6_TLV_ATTR_CLASS,                    /* u8, 3 bit flags */
+       IPV6_TLV_ATTR_ALIGN_MULT,               /* u8, 1 to 16 */
+       IPV6_TLV_ATTR_ALIGN_OFF,                /* u8, 0 to 15 */
+       IPV6_TLV_ATTR_MIN_DATA_LEN,             /* u8 (option data length) */
+       IPV6_TLV_ATTR_MAX_DATA_LEN,             /* u8 (option data length) */
+       IPV6_TLV_ATTR_DATA_LEN_MULT,            /* u8, 1 to 16 */
+       IPV6_TLV_ATTR_DATA_LEN_OFF,             /* u8, 0 to 15 */
+
+       __IPV6_TLV_ATTR_MAX,
+};
+
+#define IPV6_TLV_ATTR_MAX              (__IPV6_TLV_ATTR_MAX - 1)
+
+enum {
+       IPV6_TLV_CMD_SET,
+       IPV6_TLV_CMD_UNSET,
+       IPV6_TLV_CMD_GET,
+
+       __IPV6_TLV_CMD_MAX,
+};
 
 /* TLV permissions values */
 enum {
diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c
index 53e92fd..0b56f7a 100644
--- a/net/ipv6/exthdrs_core.c
+++ b/net/ipv6/exthdrs_core.c
@@ -3,7 +3,9 @@
  * not configured or static.
  */
 #include <linux/export.h>
+#include <net/genetlink.h>
 #include <net/ipv6.h>
+#include <uapi/linux/genetlink.h>
 
 /*
  * find out if nexthdr is a well-known extension header or a protocol
@@ -657,6 +659,284 @@ int tlv_unset_params(struct tlv_param_table 
*tlv_param_table,
 }
 EXPORT_SYMBOL(tlv_unset_params);
 
+const struct nla_policy tlv_nl_policy[IPV6_TLV_ATTR_MAX + 1] = {
+       [IPV6_TLV_ATTR_TYPE] =          { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_ORDER] =         { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_ADMIN_PERM] =    { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_USER_PERM] =     { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_CLASS] =         { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_ALIGN_MULT] =    { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_ALIGN_OFF] =     { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_MIN_DATA_LEN] =  { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_MAX_DATA_LEN] =  { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_DATA_LEN_OFF] =  { .type = NLA_U8, },
+       [IPV6_TLV_ATTR_DATA_LEN_MULT] = { .type = NLA_U8, },
+};
+EXPORT_SYMBOL(tlv_nl_policy);
+
+int tlv_nl_cmd_set(struct tlv_param_table *tlv_param_table,
+                  struct genl_family *tlv_nl_family,
+                  struct sk_buff *skb, struct genl_info *info)
+{
+       struct tlv_params new_params;
+       struct tlv_tx_params *tptx;
+       struct tlv_proc *tproc;
+       int retv = -EINVAL, i;
+       u8 tlv_type, v;
+
+       if (!info->attrs[IPV6_TLV_ATTR_TYPE])
+               return -EINVAL;
+
+       tlv_type = nla_get_u8(info->attrs[IPV6_TLV_ATTR_TYPE]);
+       if (tlv_type < 2)
+               return -EINVAL;
+
+       rcu_read_lock();
+
+       /* Base new parameters on existing ones */
+       tproc = tlv_get_proc(tlv_param_table, tlv_type);
+       new_params = tproc->params;
+
+       if (info->attrs[IPV6_TLV_ATTR_ORDER]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_ORDER]);
+               if (v) {
+                       for (i = 2; i < 256; i++) {
+                               tproc = tlv_get_proc(tlv_param_table, i);
+                               tptx = &tproc->params.t;
+
+                               /* Preferred orders must be unique */
+                               if (tptx->preferred_order == v &&
+                                   i != tlv_type) {
+                                       retv = -EALREADY;
+                                       goto out;
+                               }
+                       }
+                       new_params.t.preferred_order = v;
+               }
+       }
+
+       if (!new_params.t.preferred_order) {
+               unsigned long check_map[BITS_TO_LONGS(255)];
+               int pos;
+
+               /* Preferred order not specified, automatically set one.
+                * This is chosen to be the first value after the greatest
+                * order in use.
+                */
+               memset(check_map, 0, sizeof(check_map));
+
+               for (i = 2; i < 256; i++) {
+                       unsigned int order;
+
+                       tproc = tlv_get_proc(tlv_param_table, i);
+                       tptx = &tproc->params.t;
+                       order = tptx->preferred_order;
+
+                       if (!order)
+                               continue;
+
+                       WARN_ON(test_bit(255 - order, check_map));
+                       set_bit(255 - order, check_map);
+               }
+
+               pos = find_first_bit(check_map, 255);
+               if (pos)
+                       new_params.t.preferred_order = 255 - (pos - 1);
+               else
+                       new_params.t.preferred_order = 255 -
+                           find_first_zero_bit(check_map, sizeof(check_map));
+       }
+
+       if (info->attrs[IPV6_TLV_ATTR_ADMIN_PERM]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_ADMIN_PERM]);
+               if (v > IPV6_TLV_PERM_MAX)
+                       goto out;
+               new_params.t.admin_perm = v;
+       }
+
+       if (info->attrs[IPV6_TLV_ATTR_USER_PERM]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_USER_PERM]);
+               if (v > IPV6_TLV_PERM_MAX)
+                       goto out;
+               new_params.t.user_perm = v;
+       }
+
+       if (info->attrs[IPV6_TLV_ATTR_CLASS]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_CLASS]);
+               if (v > IPV6_TLV_CLASS_MAX)
+                       goto out;
+               new_params.t.class = v;
+       }
+
+       if (info->attrs[IPV6_TLV_ATTR_ALIGN_MULT]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_ALIGN_MULT]);
+               if (v > 16 || v < 1)
+                       goto out;
+               new_params.t.align_mult = v - 1;
+       }
+
+       if (info->attrs[IPV6_TLV_ATTR_ALIGN_OFF]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_ALIGN_OFF]);
+               if (v > 15)
+                       goto out;
+               new_params.t.align_off = v;
+       }
+
+       if (info->attrs[IPV6_TLV_ATTR_MAX_DATA_LEN])
+               new_params.t.max_data_len =
+                   nla_get_u8(info->attrs[IPV6_TLV_ATTR_MAX_DATA_LEN]);
+
+       if (info->attrs[IPV6_TLV_ATTR_MIN_DATA_LEN])
+               new_params.t.min_data_len =
+                   nla_get_u8(info->attrs[IPV6_TLV_ATTR_MIN_DATA_LEN]);
+
+       if (info->attrs[IPV6_TLV_ATTR_DATA_LEN_MULT]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_DATA_LEN_MULT]);
+               if (v > 16 || v < 1)
+                       goto out;
+               new_params.t.data_len_mult = v - 1;
+       }
+
+       if (info->attrs[IPV6_TLV_ATTR_DATA_LEN_OFF]) {
+               v = nla_get_u8(info->attrs[IPV6_TLV_ATTR_DATA_LEN_OFF]);
+               if (v > 15)
+                       goto out;
+               new_params.t.data_len_off = v;
+       }
+
+       retv = tlv_set_params(tlv_param_table, tlv_type, &new_params);
+
+out:
+       rcu_read_unlock();
+       return retv;
+}
+EXPORT_SYMBOL(tlv_nl_cmd_set);
+
+int tlv_nl_cmd_unset(struct tlv_param_table *tlv_param_table,
+                    struct genl_family *tlv_nl_family,
+                    struct sk_buff *skb, struct genl_info *info)
+{
+       unsigned int tlv_type;
+
+       if (!info->attrs[IPV6_TLV_ATTR_TYPE])
+               return -EINVAL;
+
+       tlv_type = nla_get_u8(info->attrs[IPV6_TLV_ATTR_TYPE]);
+       if (tlv_type < 2)
+               return -EINVAL;
+
+       return tlv_unset_params(tlv_param_table, tlv_type);
+}
+EXPORT_SYMBOL(tlv_nl_cmd_unset);
+
+int tlv_fill_info(struct tlv_param_table *tlv_param_table,
+                 int tlv_type, struct sk_buff *msg, bool admin)
+{
+       struct tlv_proc *tproc;
+       struct tlv_params *tp;
+       int ret = 0;
+
+       rcu_read_lock();
+
+       tproc = tlv_get_proc(tlv_param_table, tlv_type);
+       tp = &tproc->params;
+
+       if (nla_put_u8(msg, IPV6_TLV_ATTR_TYPE, tlv_type) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_ORDER, tp->t.preferred_order) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_USER_PERM, tp->t.user_perm) ||
+           (admin && nla_put_u8(msg, IPV6_TLV_ATTR_ADMIN_PERM,
+                                tp->t.admin_perm)) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_CLASS, tp->t.class) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_ALIGN_MULT, tp->t.align_mult + 1) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_ALIGN_OFF, tp->t.align_off) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_MIN_DATA_LEN, tp->t.min_data_len) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_MAX_DATA_LEN, tp->t.max_data_len) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_DATA_LEN_MULT,
+                      tp->t.data_len_mult + 1) ||
+           nla_put_u8(msg, IPV6_TLV_ATTR_DATA_LEN_OFF, tp->t.data_len_off))
+               ret = -1;
+
+       rcu_read_unlock();
+
+       return ret;
+}
+EXPORT_SYMBOL(tlv_fill_info);
+
+static int tlv_dump_info(struct tlv_param_table *tlv_param_table,
+                        struct genl_family *tlv_nl_family,
+                        int tlv_type, u32 portid, u32 seq, u32 flags,
+                        struct sk_buff *skb, u8 cmd, bool admin)
+{
+       void *hdr;
+
+       hdr = genlmsg_put(skb, portid, seq, tlv_nl_family, flags, cmd);
+       if (!hdr)
+               return -ENOMEM;
+
+       if (tlv_fill_info(tlv_param_table, tlv_type, skb, admin) < 0) {
+               genlmsg_cancel(skb, hdr);
+               return -EMSGSIZE;
+       }
+
+       genlmsg_end(skb, hdr);
+
+       return 0;
+}
+
+int tlv_nl_cmd_get(struct tlv_param_table *tlv_param_table,
+                  struct genl_family *tlv_nl_family,
+                  struct sk_buff *skb, struct genl_info *info)
+{
+       struct sk_buff *msg;
+       int ret, tlv_type;
+
+       if (!info->attrs[IPV6_TLV_ATTR_TYPE])
+               return -EINVAL;
+
+       tlv_type = nla_get_u8(info->attrs[IPV6_TLV_ATTR_TYPE]);
+       if (tlv_type < 2)
+               return -EINVAL;
+
+       msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+       if (!msg)
+               return -ENOMEM;
+
+       ret = tlv_dump_info(tlv_param_table, tlv_nl_family,
+                           tlv_type, info->snd_portid, info->snd_seq, 0, msg,
+                           info->genlhdr->cmd,
+                           netlink_capable(skb, CAP_NET_ADMIN));
+       if (ret < 0) {
+               nlmsg_free(msg);
+               return ret;
+       }
+
+       return genlmsg_reply(msg, info);
+}
+EXPORT_SYMBOL(tlv_nl_cmd_get);
+
+int tlv_nl_dump(struct tlv_param_table *tlv_param_table,
+               struct genl_family *tlv_nl_family,
+               struct sk_buff *skb, struct netlink_callback *cb)
+{
+       int idx = 0, ret, i;
+
+       for (i = 2; i < 256; i++) {
+               if (idx++ < cb->args[0])
+                       continue;
+               ret = tlv_dump_info(tlv_param_table, tlv_nl_family, i,
+                                   NETLINK_CB(cb->skb).portid,
+                                   cb->nlh->nlmsg_seq, NLM_F_MULTI,
+                                   skb, IPV6_TLV_CMD_GET,
+                                   netlink_capable(cb->skb, CAP_NET_ADMIN));
+               if (ret)
+                       break;
+       }
+
+       cb->args[0] = idx;
+       return skb->len;
+}
+EXPORT_SYMBOL(tlv_nl_dump);
+
 int exthdrs_init(struct tlv_param_table *tlv_param_table,
                 const struct tlv_proc_init *tlv_init_params,
                 int num_init_params)
diff --git a/net/ipv6/exthdrs_options.c b/net/ipv6/exthdrs_options.c
index 042ca14..87f3118 100644
--- a/net/ipv6/exthdrs_options.c
+++ b/net/ipv6/exthdrs_options.c
@@ -6,6 +6,7 @@
 #include <linux/socket.h>
 #include <linux/types.h>
 #include <net/calipso.h>
+#include <net/genetlink.h>
 #include <net/ipv6.h>
 #include <net/ip6_route.h>
 #if IS_ENABLED(CONFIG_IPV6_MIP6)
@@ -256,15 +257,91 @@ static const struct tlv_proc_init tlv_init_params[] 
__initconst = {
 struct tlv_param_table __rcu ipv6_tlv_param_table;
 EXPORT_SYMBOL(ipv6_tlv_param_table);
 
+static int ipv6_tlv_nl_cmd_set(struct sk_buff *skb, struct genl_info *info);
+static int ipv6_tlv_nl_cmd_unset(struct sk_buff *skb, struct genl_info *info);
+static int ipv6_tlv_nl_cmd_get(struct sk_buff *skb, struct genl_info *info);
+static int ipv6_tlv_nl_dump(struct sk_buff *skb, struct netlink_callback *cb);
+
+static const struct genl_ops ipv6_tlv_nl_ops[] = {
+{
+       .cmd = IPV6_TLV_CMD_SET,
+       .doit = ipv6_tlv_nl_cmd_set,
+       .flags = GENL_ADMIN_PERM,
+},
+{
+       .cmd = IPV6_TLV_CMD_UNSET,
+       .doit = ipv6_tlv_nl_cmd_unset,
+       .flags = GENL_ADMIN_PERM,
+},
+{
+       .cmd = IPV6_TLV_CMD_GET,
+       .doit = ipv6_tlv_nl_cmd_get,
+       .dumpit = ipv6_tlv_nl_dump,
+},
+};
+
+struct genl_family ipv6_tlv_nl_family __ro_after_init = {
+       .hdrsize        = 0,
+       .name           = IPV6_TLV_GENL_NAME,
+       .version        = IPV6_TLV_GENL_VERSION,
+       .maxattr        = IPV6_TLV_ATTR_MAX,
+       .policy         = tlv_nl_policy,
+       .netnsok        = true,
+       .parallel_ops   = true,
+       .ops            = ipv6_tlv_nl_ops,
+       .n_ops          = ARRAY_SIZE(ipv6_tlv_nl_ops),
+       .module         = THIS_MODULE,
+};
+
+static int ipv6_tlv_nl_cmd_set(struct sk_buff *skb, struct genl_info *info)
+{
+       return tlv_nl_cmd_set(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+                             skb, info);
+}
+
+static int ipv6_tlv_nl_cmd_unset(struct sk_buff *skb, struct genl_info *info)
+{
+       return tlv_nl_cmd_unset(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+                               skb, info);
+}
+
+static int ipv6_tlv_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
+{
+       return tlv_nl_cmd_get(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+                             skb, info);
+}
+
+static int ipv6_tlv_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+       return tlv_nl_dump(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+                          skb, cb);
+}
+
 static int __init ipv6_exthdrs_init(void)
 {
-       return exthdrs_init(&ipv6_tlv_param_table, tlv_init_params,
-                           ARRAY_SIZE(tlv_init_params));
+       int err;
+
+       err = genl_register_family(&ipv6_tlv_nl_family);
+       if (err)
+               goto out;
+
+       err = exthdrs_init(&ipv6_tlv_param_table, tlv_init_params,
+                          ARRAY_SIZE(tlv_init_params));
+       if (err)
+               goto out_unregister_genl;
+
+       return 0;
+
+out_unregister_genl:
+       genl_unregister_family(&ipv6_tlv_nl_family);
+out:
+       return err;
 }
 module_init(ipv6_exthdrs_init);
 
 static void __exit ipv6_exthdrs_fini(void)
 {
        exthdrs_fini(&ipv6_tlv_param_table);
+       genl_unregister_family(&ipv6_tlv_nl_family);
 }
 module_exit(ipv6_exthdrs_fini);
-- 
2.7.4

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