tools: ynl: support creating non-genl sockets

Classic netlink has static family IDs specified in YAML,
there is no family name -> ID lookup. Support providing
the ID info to the library via the generated struct and
make library use it. Since NETLINK_ROUTE is ID 0 we need
an extra boolean to indicate classic_id is to be used.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20250410014658.782120-8-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/net/ynl/lib/ynl.c b/tools/net/ynl/lib/ynl.c
index ce32cb35007d6f57ee55b4cff5afcac93c0e3d37..b9fda1a99453ae51c4ba1580af645fc35dd3745a 100644 (file)
--- a/tools/net/ynl/lib/ynl.c
+++ b/tools/net/ynl/lib/ynl.c
@@ -663,6 +663,7 @@ ynl_sock_create(const struct ynl_family *yf, struct ynl_error *yse)
        struct sockaddr_nl addr;
        struct ynl_sock *ys;
        socklen_t addrlen;
+       int sock_type;
        int one = 1;
 
        ys = malloc(sizeof(*ys) + 2 * YNL_SOCKET_BUFFER_SIZE);
@@ -675,7 +676,9 @@ ynl_sock_create(const struct ynl_family *yf, struct ynl_error *yse)
        ys->rx_buf = &ys->raw_buf[YNL_SOCKET_BUFFER_SIZE];
        ys->ntf_last_next = &ys->ntf_first;
 
-       ys->socket = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
+       sock_type = yf->is_classic ? yf->classic_id : NETLINK_GENERIC;
+
+       ys->socket = socket(AF_NETLINK, SOCK_RAW, sock_type);
        if (ys->socket < 0) {
                __perr(yse, "failed to create a netlink socket");
                goto err_free_sock;
@@ -708,8 +711,9 @@ ynl_sock_create(const struct ynl_family *yf, struct ynl_error *yse)
        ys->portid = addr.nl_pid;
        ys->seq = random();
 
-
-       if (ynl_sock_read_family(ys, yf->name)) {
+       if (yf->is_classic) {
+               ys->family_id = yf->classic_id;
+       } else if (ynl_sock_read_family(ys, yf->name)) {
                if (yse)
                        memcpy(yse, &ys->err, sizeof(*yse));
                goto err_close_sock;
@@ -791,13 +795,21 @@ static int ynl_ntf_parse(struct ynl_sock *ys, const struct nlmsghdr *nlh)
        struct ynl_parse_arg yarg = { .ys = ys, };
        const struct ynl_ntf_info *info;
        struct ynl_ntf_base_type *rsp;
-       struct genlmsghdr *gehdr;
+       __u32 cmd;
        int ret;
 
-       gehdr = ynl_nlmsg_data(nlh);
-       if (gehdr->cmd >= ys->family->ntf_info_size)
+       if (ys->family->is_classic) {
+               cmd = nlh->nlmsg_type;
+       } else {
+               struct genlmsghdr *gehdr;
+
+               gehdr = ynl_nlmsg_data(nlh);
+               cmd = gehdr->cmd;
+       }
+
+       if (cmd >= ys->family->ntf_info_size)
                return YNL_PARSE_CB_ERROR;
-       info = &ys->family->ntf_info[gehdr->cmd];
+       info = &ys->family->ntf_info[cmd];
        if (!info->cb)
                return YNL_PARSE_CB_ERROR;
 
@@ -811,7 +823,7 @@ static int ynl_ntf_parse(struct ynl_sock *ys, const struct nlmsghdr *nlh)
                goto err_free;
 
        rsp->family = nlh->nlmsg_type;
-       rsp->cmd = gehdr->cmd;
+       rsp->cmd = cmd;
 
        *ys->ntf_last_next = rsp;
        ys->ntf_last_next = &rsp->next;
@@ -863,17 +875,22 @@ int ynl_error_parse(struct ynl_parse_arg *yarg, const char *msg)
 static int
 ynl_check_alien(struct ynl_sock *ys, const struct nlmsghdr *nlh, __u32 rsp_cmd)
 {
-       struct genlmsghdr *gehdr;
+       if (ys->family->is_classic) {
+               if (nlh->nlmsg_type != rsp_cmd)
+                       return ynl_ntf_parse(ys, nlh);
+       } else {
+               struct genlmsghdr *gehdr;
 
-       if (ynl_nlmsg_data_len(nlh) < sizeof(*gehdr)) {
-               yerr(ys, YNL_ERROR_INV_RESP,
-                    "Kernel responded with truncated message");
-               return -1;
-       }
+               if (ynl_nlmsg_data_len(nlh) < sizeof(*gehdr)) {
+                       yerr(ys, YNL_ERROR_INV_RESP,
+                            "Kernel responded with truncated message");
+                       return -1;
+               }
 
-       gehdr = ynl_nlmsg_data(nlh);
-       if (gehdr->cmd != rsp_cmd)
-               return ynl_ntf_parse(ys, nlh);
+               gehdr = ynl_nlmsg_data(nlh);
+               if (gehdr->cmd != rsp_cmd)
+                       return ynl_ntf_parse(ys, nlh);
+       }
 
        return 0;
 }

diff --git a/tools/net/ynl/lib/ynl.h b/tools/net/ynl/lib/ynl.h
index 6cd570b283eab89bb1a532deefc8f1e4c4229080..59256e258130b73802d55d480aedab4fb7248ec9 100644 (file)
--- a/tools/net/ynl/lib/ynl.h
+++ b/tools/net/ynl/lib/ynl.h
@@ -2,6 +2,7 @@
 #ifndef __YNL_C_H
 #define __YNL_C_H 1
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <linux/genetlink.h>
 #include <linux/types.h>
@@ -48,6 +49,8 @@ struct ynl_family {
 /* private: */
        const char *name;
        size_t hdr_len;
+       bool is_classic;
+       __u16 classic_id;
        const struct ynl_ntf_info *ntf_info;
        unsigned int ntf_info_size;
 };

diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py
index a1427c5370302507377239b800c3ea4f185fc80b..9e00aac4801c27aa7507b2198f0a7cace5c8fb53 100755 (executable)
--- a/tools/net/ynl/pyynl/ynl_gen_c.py
+++ b/tools/net/ynl/pyynl/ynl_gen_c.py
@@ -971,9 +971,6 @@ class Family(SpecFamily):
     def resolve(self):
         self.resolve_up(super())
 
-        if self.yaml.get('protocol', 'genetlink') not in {'genetlink', 'genetlink-c', 'genetlink-legacy'}:
-            raise Exception("Codegen only supported for genetlink")
-
         self.c_name = c_lower(self.ident_name)
         if 'name-prefix' in self.yaml['operations']:
             self.op_prefix = c_upper(self.yaml['operations']['name-prefix'])
@@ -1020,6 +1017,9 @@ class Family(SpecFamily):
     def new_operation(self, elem, req_value, rsp_value):
         return Operation(self, elem, req_value, rsp_value)
 
+    def is_classic(self):
+        return self.proto == 'netlink-raw'
+
     def _mark_notify(self):
         for op in self.msgs.values():
             if 'notify' in op:
@@ -2730,6 +2730,9 @@ def render_user_family(family, cw, prototype):
 
     cw.block_start(f'{symbol} = ')
     cw.p(f'.name\t\t= "{family.c_name}",')
+    if family.is_classic():
+        cw.p(f'.is_classic\t= true,')
+        cw.p(f'.classic_id\t= {family.get("protonum")},')
     if family.fixed_header:
         cw.p(f'.hdr_len\t= sizeof(struct genlmsghdr) + sizeof(struct {c_lower(family.fixed_header)}),')
     else: