Merge branch 'tools-ynl-c-basic-netlink-raw-support'

Jakub Kicinski says:

====================
tools: ynl: c: basic netlink-raw support

Basic support for netlink-raw AKA classic netlink in user space C codegen.
This series is enough to read routes and addresses from the kernel
(see the samples in patches 12 and 13).

Specs need to be slightly adjusted and decorated with the c naming info.

In terms of codegen this series includes just the basic plumbing required
to skip genlmsghdr and handle request types which may technically also
be legal in genetlink-legacy but are very uncommon there.

Subsequent series will add support for:
 - handling CRUD-style notifications
 - code gen for array types classic netlink uses
 - sub-message support

v1: https://lore.kernel.org/[email protected]
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

Documentation/netlink/specs/rt_addr.yaml renamed to Documentation/netlink/specs/rt-addr.yaml

@@ -2,6 +2,7 @@
 
 name: rt-addr
 protocol: netlink-raw
+uapi-header: linux/rtnetlink.h
 protonum: 0
 
 doc:
@@ -49,6 +50,8 @@ definitions:
   -
     name: ifa-flags
     type: flags
+    name-prefix: ifa-f-
+    enum-name:
     entries:
       -
         name: secondary
@@ -124,6 +127,7 @@ attribute-sets:
 operations:
   fixed-header: ifaddrmsg
   enum-model: directional
+  name-prefix: rtm-
   list:
     -
       name: newaddr
@@ -133,11 +137,6 @@ operations:
         request:
           value: 20
           attributes: &ifaddr-all
-            - ifa-family
-            - ifa-flags
-            - ifa-prefixlen
-            - ifa-scope
-            - ifa-index
             - address
             - label
             - local
@@ -150,11 +149,6 @@ operations:
         request:
           value: 21
           attributes:
-            - ifa-family
-            - ifa-flags
-            - ifa-prefixlen
-            - ifa-scope
-            - ifa-index
             - address
             - local
     -
@@ -164,8 +158,7 @@ operations:
       dump:
         request:
           value: 22
-          attributes:
-            - ifa-index
+          attributes: []
         reply:
           value: 20
           attributes: *ifaddr-all
@@ -177,9 +170,7 @@ operations:
       do:
         request:
           value: 58
-          attributes:
-            - ifa-family
-            - ifa-index
+          attributes: []
         reply:
           value: 58
           attributes: &mcaddr-attrs
@@ -188,8 +179,7 @@ operations:
       dump:
         request:
           value: 58
-          attributes:
-            - ifa-family
+          attributes: []
         reply:
           value: 58
           attributes: *mcaddr-attrs

Documentation/netlink/specs/rt_link.yaml renamed to Documentation/netlink/specs/rt-link.yaml

@@ -2,6 +2,7 @@
 
 name: rt-route
 protocol: netlink-raw
+uapi-header: linux/rtnetlink.h
 protonum: 0
 
 doc:
@@ -11,6 +12,7 @@ definitions:
   -
     name: rtm-type
     name-prefix: rtn-
+    enum-name:
     type: enum
     entries:
       - unspec
@@ -245,21 +247,19 @@ attribute-sets:
 
 operations:
   enum-model: directional
+  fixed-header: rtmsg
+  name-prefix: rtm-
   list:
     -
       name: getroute
       doc: Dump route information.
       attribute-set: route-attrs
-      fixed-header: rtmsg
       do:
         request:
           value: 26
           attributes:
-            - rtm-family
             - src
-            - rtm-src-len
             - dst
-            - rtm-dst-len
             - iif
             - oif
             - ip-proto
@@ -271,15 +271,6 @@ operations:
         reply:
           value: 24
           attributes: &all-route-attrs
-            - rtm-family
-            - rtm-dst-len
-            - rtm-src-len
-            - rtm-tos
-            - rtm-table
-            - rtm-protocol
-            - rtm-scope
-            - rtm-type
-            - rtm-flags
             - dst
             - src
             - iif
@@ -311,16 +302,14 @@ operations:
       dump:
         request:
           value: 26
-          attributes:
-            - rtm-family
+          attributes: []
         reply:
           value: 24
           attributes: *all-route-attrs
     -
       name: newroute
       doc: Create a new route
       attribute-set: route-attrs
-      fixed-header: rtmsg
       do:
         request:
           value: 24
@@ -329,7 +318,6 @@ operations:
       name: delroute
       doc: Delete an existing route
       attribute-set: route-attrs
-      fixed-header: rtmsg
       do:
         request:
           value: 25

Documentation/netlink/specs/rt_neigh.yaml renamed to Documentation/netlink/specs/rt-neigh.yaml

@@ -62,7 +62,7 @@ Sub-messages
 ------------
 
 Several raw netlink families such as
-:doc:`rt_link<../../networking/netlink_spec/rt_link>` and
+:doc:`rt-link<../../networking/netlink_spec/rt-link>` and
 :doc:`tc<../../networking/netlink_spec/tc>` use attribute nesting as an
 abstraction to carry module specific information.
 

Documentation/netlink/specs/rt_route.yaml renamed to Documentation/netlink/specs/rt-route.yaml

@@ -29,4 +29,6 @@ CFLAGS_nfsd:=$(call get_hdr_inc,_LINUX_NFSD_NETLINK_H,nfsd_netlink.h)
 CFLAGS_ovs_datapath:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)
 CFLAGS_ovs_flow:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)
 CFLAGS_ovs_vport:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)
+CFLAGS_rt-addr:=$(call get_hdr_inc,__LINUX_RTNETLINK_H,rtnetlink.h)
+CFLAGS_rt-route:=$(call get_hdr_inc,__LINUX_RTNETLINK_H,rtnetlink.h)
 CFLAGS_tcp_metrics:=$(call get_hdr_inc,_LINUX_TCP_METRICS_H,tcp_metrics.h)

Documentation/netlink/specs/rt_rule.yaml renamed to Documentation/netlink/specs/rt-rule.yaml

@@ -25,7 +25,7 @@ SPECS_DIR:=../../../../Documentation/netlink/specs
 GENS_PATHS=$(shell grep -nrI --files-without-match \
 		'protocol: netlink' \
 		$(SPECS_DIR))
-GENS=$(patsubst $(SPECS_DIR)/%.yaml,%,${GENS_PATHS})
+GENS=$(patsubst $(SPECS_DIR)/%.yaml,%,${GENS_PATHS}) rt-addr rt-route
 SRCS=$(patsubst %,%-user.c,${GENS})
 HDRS=$(patsubst %,%-user.h,${GENS})
 OBJS=$(patsubst %,%-user.o,${GENS})

Documentation/userspace-api/netlink/netlink-raw.rst

@@ -94,6 +94,9 @@ struct ynl_ntf_base_type {
 	unsigned char data[] __attribute__((aligned(8)));
 };
 
+struct nlmsghdr *ynl_msg_start_req(struct ynl_sock *ys, __u32 id);
+struct nlmsghdr *ynl_msg_start_dump(struct ynl_sock *ys, __u32 id);
+
 struct nlmsghdr *
 ynl_gemsg_start_req(struct ynl_sock *ys, __u32 id, __u8 cmd, __u8 version);
 struct nlmsghdr *

tools/net/ynl/Makefile.deps

@@ -451,14 +451,14 @@ ynl_gemsg_start(struct ynl_sock *ys, __u32 id, __u16 flags,
 	return nlh;
 }
 
-void ynl_msg_start_req(struct ynl_sock *ys, __u32 id)
+struct nlmsghdr *ynl_msg_start_req(struct ynl_sock *ys, __u32 id)
 {
-	ynl_msg_start(ys, id, NLM_F_REQUEST | NLM_F_ACK);
+	return ynl_msg_start(ys, id, NLM_F_REQUEST | NLM_F_ACK);
 }
 
-void ynl_msg_start_dump(struct ynl_sock *ys, __u32 id)
+struct nlmsghdr *ynl_msg_start_dump(struct ynl_sock *ys, __u32 id)
 {
-	ynl_msg_start(ys, id, NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP);
+	return ynl_msg_start(ys, id, NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP);
 }
 
 struct nlmsghdr *
@@ -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;
 }