tools: ynl: create local attribute helpers

Don't use mnl attr helpers, we're trying to remove the libmnl
dependency. Create both signed and unsigned helpers, libmnl
had unsigned helpers, so code generator no longer needs
the mnl_type() hack.

The new helpers are written from first principles, but are
hopefully not too buggy.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 204 insertions, 36 deletions

diff --git a/tools/net/ynl/lib/ynl-priv.h b/tools/net/ynl/lib/ynl-priv.h
index eaa0d432366c..d42d44a77dcb 100644
--- a/tools/net/ynl/lib/ynl-priv.h
+++ b/tools/net/ynl/lib/ynl-priv.h
@@ -127,45 +127,213 @@ int ynl_error_parse(struct ynl_parse_arg *yarg, const char *msg);
 
 /* Attribute helpers */
 
-static inline __u64 mnl_attr_get_uint(const struct nlattr *attr)
+static inline void *ynl_nlmsg_end_addr(const struct nlmsghdr *nlh)
 {
-	switch (mnl_attr_get_payload_len(attr)) {
+	return (char *)nlh + nlh->nlmsg_len;
+}
+
+static inline unsigned int ynl_attr_type(const struct nlattr *attr)
+{
+	return attr->nla_type & NLA_TYPE_MASK;
+}
+
+static inline unsigned int ynl_attr_data_len(const struct nlattr *attr)
+{
+	return attr->nla_len - NLA_HDRLEN;
+}
+
+static inline void *ynl_attr_data(const struct nlattr *attr)
+{
+	return (unsigned char *)attr + NLA_HDRLEN;
+}
+
+static inline struct nlattr *
+ynl_attr_nest_start(struct nlmsghdr *nlh, unsigned int attr_type)
+{
+	struct nlattr *attr;
+
+	attr = ynl_nlmsg_end_addr(nlh);
+	attr->nla_type = attr_type | NLA_F_NESTED;
+	nlh->nlmsg_len += NLA_HDRLEN;
+
+	return attr;
+}
+
+static inline void
+ynl_attr_nest_end(struct nlmsghdr *nlh, struct nlattr *attr)
+{
+	attr->nla_len = (char *)ynl_nlmsg_end_addr(nlh) - (char *)attr;
+}
+
+static inline void
+ynl_attr_put(struct nlmsghdr *nlh, unsigned int attr_type,
+	     const void *value, size_t size)
+{
+	struct nlattr *attr;
+
+	attr = ynl_nlmsg_end_addr(nlh);
+	attr->nla_type = attr_type;
+	attr->nla_len = NLA_HDRLEN + size;
+
+	memcpy(ynl_attr_data(attr), value, size);
+
+	nlh->nlmsg_len += NLMSG_ALIGN(attr->nla_len);
+}
+
+static inline void
+ynl_attr_put_str(struct nlmsghdr *nlh, unsigned int attr_type, const char *str)
+{
+	struct nlattr *attr;
+	const char *end;
+
+	attr = ynl_nlmsg_end_addr(nlh);
+	attr->nla_type = attr_type;
+
+	end = stpcpy(ynl_attr_data(attr), str);
+	attr->nla_len =
+		NLA_HDRLEN + NLA_ALIGN(end - (char *)ynl_attr_data(attr));
+
+	nlh->nlmsg_len += NLMSG_ALIGN(attr->nla_len);
+}
+
+static inline const char *ynl_attr_get_str(const struct nlattr *attr)
+{
+	return (const char *)ynl_attr_data(attr);
+}
+
+static inline __s8 ynl_attr_get_s8(const struct nlattr *attr)
+{
+	return *(__s8 *)ynl_attr_data(attr);
+}
+
+static inline __s16 ynl_attr_get_s16(const struct nlattr *attr)
+{
+	return *(__s16 *)ynl_attr_data(attr);
+}
+
+static inline __s32 ynl_attr_get_s32(const struct nlattr *attr)
+{
+	return *(__s32 *)ynl_attr_data(attr);
+}
+
+static inline __s64 ynl_attr_get_s64(const struct nlattr *attr)
+{
+	__s64 tmp;
+
+	memcpy(&tmp, (unsigned char *)(attr + 1), sizeof(tmp));
+	return tmp;
+}
+
+static inline __u8 ynl_attr_get_u8(const struct nlattr *attr)
+{
+	return *(__u8 *)ynl_attr_data(attr);
+}
+
+static inline __u16 ynl_attr_get_u16(const struct nlattr *attr)
+{
+	return *(__u16 *)ynl_attr_data(attr);
+}
+
+static inline __u32 ynl_attr_get_u32(const struct nlattr *attr)
+{
+	return *(__u32 *)ynl_attr_data(attr);
+}
+
+static inline __u64 ynl_attr_get_u64(const struct nlattr *attr)
+{
+	__u64 tmp;
+
+	memcpy(&tmp, (unsigned char *)(attr + 1), sizeof(tmp));
+	return tmp;
+}
+
+static inline void
+ynl_attr_put_s8(struct nlmsghdr *nlh, unsigned int attr_type, __s8 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline void
+ynl_attr_put_s16(struct nlmsghdr *nlh, unsigned int attr_type, __s16 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline void
+ynl_attr_put_s32(struct nlmsghdr *nlh, unsigned int attr_type, __s32 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline void
+ynl_attr_put_s64(struct nlmsghdr *nlh, unsigned int attr_type, __s64 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline void
+ynl_attr_put_u8(struct nlmsghdr *nlh, unsigned int attr_type, __u8 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline void
+ynl_attr_put_u16(struct nlmsghdr *nlh, unsigned int attr_type, __u16 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline void
+ynl_attr_put_u32(struct nlmsghdr *nlh, unsigned int attr_type, __u32 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline void
+ynl_attr_put_u64(struct nlmsghdr *nlh, unsigned int attr_type, __u64 value)
+{
+	ynl_attr_put(nlh, attr_type, &value, sizeof(value));
+}
+
+static inline __u64 ynl_attr_get_uint(const struct nlattr *attr)
+{
+	switch (ynl_attr_data_len(attr)) {
 	case 4:
-		return mnl_attr_get_u32(attr);
+		return ynl_attr_get_u32(attr);
 	case 8:
-		return mnl_attr_get_u64(attr);
+		return ynl_attr_get_u64(attr);
 	default:
 		return 0;
 	}
 }
 
-static inline __s64 mnl_attr_get_sint(const struct nlattr *attr)
+static inline __s64 ynl_attr_get_sint(const struct nlattr *attr)
 {
-	switch (mnl_attr_get_payload_len(attr)) {
+	switch (ynl_attr_data_len(attr)) {
 	case 4:
-		return mnl_attr_get_u32(attr);
+		return ynl_attr_get_s32(attr);
 	case 8:
-		return mnl_attr_get_u64(attr);
+		return ynl_attr_get_s64(attr);
 	default:
 		return 0;
 	}
 }
 
 static inline void
-mnl_attr_put_uint(struct nlmsghdr *nlh, __u16 type, __u64 data)
+ynl_attr_put_uint(struct nlmsghdr *nlh, __u16 type, __u64 data)
 {
 	if ((__u32)data == (__u64)data)
-		mnl_attr_put_u32(nlh, type, data);
+		ynl_attr_put_u32(nlh, type, data);
 	else
-		mnl_attr_put_u64(nlh, type, data);
+		ynl_attr_put_u64(nlh, type, data);
 }
 
 static inline void
-mnl_attr_put_sint(struct nlmsghdr *nlh, __u16 type, __s64 data)
+ynl_attr_put_sint(struct nlmsghdr *nlh, __u16 type, __s64 data)
 {
 	if ((__s32)data == (__s64)data)
-		mnl_attr_put_u32(nlh, type, data);
+		ynl_attr_put_s32(nlh, type, data);
 	else
-		mnl_attr_put_u64(nlh, type, data);
+		ynl_attr_put_s64(nlh, type, data);
 }
 #endif
diff --git a/tools/net/ynl/lib/ynl.c b/tools/net/ynl/lib/ynl.c
index 6e6d474c8366..b9ed587af676 100644
--- a/tools/net/ynl/lib/ynl.c
+++ b/tools/net/ynl/lib/ynl.c
@@ -94,7 +94,7 @@ ynl_err_walk(struct ynl_sock *ys, void *start, void *end, unsigned int off,
 
 	mnl_attr_for_each_payload(start, data_len) {
 		astart_off = (char *)attr - (char *)start;
-		aend_off = astart_off + mnl_attr_get_payload_len(attr);
+		aend_off = astart_off + ynl_attr_data_len(attr);
 		if (aend_off <= off)
 			continue;
 
@@ -106,7 +106,7 @@ ynl_err_walk(struct ynl_sock *ys, void *start, void *end, unsigned int off,
 
 	off -= astart_off;
 
-	type = mnl_attr_get_type(attr);
+	type = ynl_attr_type(attr);
 
 	if (ynl_err_walk_report_one(policy, type, str, str_sz, &n))
 		return n;
@@ -124,8 +124,8 @@ ynl_err_walk(struct ynl_sock *ys, void *start, void *end, unsigned int off,
 	}
 
 	off -= sizeof(struct nlattr);
-	start =  mnl_attr_get_payload(attr);
-	end = start + mnl_attr_get_payload_len(attr);
+	start =  ynl_attr_data(attr);
+	end = start + ynl_attr_data_len(attr);
 
 	return n + ynl_err_walk(ys, start, end, off, policy->table[type].nest,
 				&str[n], str_sz - n, nest_pol);
@@ -153,8 +153,8 @@ ynl_ext_ack_check(struct ynl_sock *ys, const struct nlmsghdr *nlh,
 	mnl_attr_for_each(attr, nlh, hlen) {
 		unsigned int len, type;
 
-		len = mnl_attr_get_payload_len(attr);
-		type = mnl_attr_get_type(attr);
+		len = ynl_attr_data_len(attr);
+		type = ynl_attr_type(attr);
 
 		if (type > NLMSGERR_ATTR_MAX)
 			continue;
@@ -169,7 +169,7 @@ ynl_ext_ack_check(struct ynl_sock *ys, const struct nlmsghdr *nlh,
 				return MNL_CB_ERROR;
 			break;
 		case NLMSGERR_ATTR_MSG:
-			str = mnl_attr_get_payload(attr);
+			str = ynl_attr_get_str(attr);
 			if (str[len - 1])
 				return MNL_CB_ERROR;
 			break;
@@ -185,7 +185,7 @@ ynl_ext_ack_check(struct ynl_sock *ys, const struct nlmsghdr *nlh,
 		unsigned int n, off;
 		void *start, *end;
 
-		ys->err.attr_offs = mnl_attr_get_u32(tb[NLMSGERR_ATTR_OFFS]);
+		ys->err.attr_offs = ynl_attr_get_u32(tb[NLMSGERR_ATTR_OFFS]);
 
 		n = snprintf(bad_attr, sizeof(bad_attr), "%sbad attribute: ",
 			     str ? " (" : "");
@@ -211,7 +211,7 @@ ynl_ext_ack_check(struct ynl_sock *ys, const struct nlmsghdr *nlh,
 		void *start, *end;
 		int n2;
 
-		type = mnl_attr_get_u32(tb[NLMSGERR_ATTR_MISS_TYPE]);
+		type = ynl_attr_get_u32(tb[NLMSGERR_ATTR_MISS_TYPE]);
 
 		n = snprintf(miss_attr, sizeof(miss_attr), "%smissing attribute: ",
 			     bad_attr[0] ? ", " : (str ? " (" : ""));
@@ -222,7 +222,7 @@ ynl_ext_ack_check(struct ynl_sock *ys, const struct nlmsghdr *nlh,
 
 		nest_pol = ys->req_policy;
 		if (tb[NLMSGERR_ATTR_MISS_NEST]) {
-			off = mnl_attr_get_u32(tb[NLMSGERR_ATTR_MISS_NEST]);
+			off = ynl_attr_get_u32(tb[NLMSGERR_ATTR_MISS_NEST]);
 			off -= sizeof(struct nlmsghdr);
 			off -= ys->family->hdr_len;
 
@@ -314,9 +314,9 @@ int ynl_attr_validate(struct ynl_parse_arg *yarg, const struct nlattr *attr)
 	unsigned int type, len;
 	unsigned char *data;
 
-	data = mnl_attr_get_payload(attr);
-	len = mnl_attr_get_payload_len(attr);
-	type = mnl_attr_get_type(attr);
+	data = ynl_attr_data(attr);
+	len = ynl_attr_data_len(attr);
+	type = ynl_attr_type(attr);
 	if (type > yarg->rsp_policy->max_attr) {
 		yerr(yarg->ys, YNL_ERROR_INTERNAL,
 		     "Internal error, validating unknown attribute");
@@ -514,11 +514,11 @@ ynl_get_family_info_mcast(struct ynl_sock *ys, const struct nlattr *mcasts)
 	i = 0;
 	mnl_attr_for_each_nested(entry, mcasts) {
 		mnl_attr_for_each_nested(attr, entry) {
-			if (mnl_attr_get_type(attr) == CTRL_ATTR_MCAST_GRP_ID)
-				ys->mcast_groups[i].id = mnl_attr_get_u32(attr);
-			if (mnl_attr_get_type(attr) == CTRL_ATTR_MCAST_GRP_NAME) {
+			if (ynl_attr_type(attr) == CTRL_ATTR_MCAST_GRP_ID)
+				ys->mcast_groups[i].id = ynl_attr_get_u32(attr);
+			if (ynl_attr_type(attr) == CTRL_ATTR_MCAST_GRP_NAME) {
 				strncpy(ys->mcast_groups[i].name,
-					mnl_attr_get_str(attr),
+					ynl_attr_get_str(attr),
 					GENL_NAMSIZ - 1);
 				ys->mcast_groups[i].name[GENL_NAMSIZ - 1] = 0;
 			}
@@ -536,19 +536,19 @@ static int ynl_get_family_info_cb(const struct nlmsghdr *nlh, void *data)
 	bool found_id = true;
 
 	mnl_attr_for_each(attr, nlh, sizeof(struct genlmsghdr)) {
-		if (mnl_attr_get_type(attr) == CTRL_ATTR_MCAST_GROUPS)
+		if (ynl_attr_type(attr) == CTRL_ATTR_MCAST_GROUPS)
 			if (ynl_get_family_info_mcast(ys, attr))
 				return MNL_CB_ERROR;
 
-		if (mnl_attr_get_type(attr) != CTRL_ATTR_FAMILY_ID)
+		if (ynl_attr_type(attr) != CTRL_ATTR_FAMILY_ID)
 			continue;
 
-		if (mnl_attr_get_payload_len(attr) != sizeof(__u16)) {
+		if (ynl_attr_data_len(attr) != sizeof(__u16)) {
 			yerr(ys, YNL_ERROR_ATTR_INVALID, "Invalid family ID");
 			return MNL_CB_ERROR;
 		}
 
-		ys->family_id = mnl_attr_get_u16(attr);
+		ys->family_id = ynl_attr_get_u16(attr);
 		found_id = true;
 	}
 
@@ -566,7 +566,7 @@ static int ynl_sock_read_family(struct ynl_sock *ys, const char *family_name)
 	int err;
 
 	nlh = ynl_gemsg_start_req(ys, GENL_ID_CTRL, CTRL_CMD_GETFAMILY, 1);
-	mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name);
+	ynl_attr_put_str(nlh, CTRL_ATTR_FAMILY_NAME, family_name);
 
 	err = mnl_socket_sendto(ys->sock, nlh, nlh->nlmsg_len);
 	if (err < 0) {