Subject: [PATCH 1/3] ip: Use the `struct fib_rule_hdr` for rules

From: Donald Sharp <[email-masked]>
Date: Sat, 17 Feb 2018 07:47:51 -0500

The iprule.c code was using `struct rtmsg` as the data
type to pass into the kernel for the netlink message.
While 'struct rtmsg' and `struct fib_rule_hdr` are
the same size and mostly the same, we should use
the correct data structure.  This commit translates
the data structures to have iprule.c use the correct
one.

Additionally copy over the modified fib_rules.h file

Signed-off-by: Donald Sharp <[email-masked]>
---
 include/linux/fib_rules.h |   2 +-
 ip/iprule.c               | 105 ++++++++++++++++++++++++----------------------
 2 files changed, 56 insertions(+), 51 deletions(-)

diff --git a/include/linux/fib_rules.h b/include/linux/fib_rules.h
index bbf02a63..21f1fbf3 100644
--- a/include/linux/fib_rules.h
+++ b/include/linux/fib_rules.h
@@ -22,8 +22,8 @@ struct fib_rule_hdr {
 	__u8		tos;
 
 	__u8		table;
+	__u8		proto;	/* reserved */
 	__u8		res1;	/* reserved */
-	__u8		res2;	/* reserved */
 	__u8		action;
 
 	__u32		flags;
diff --git a/ip/iprule.c b/ip/iprule.c
index 854a3d8e..82e22fee 100644
--- a/ip/iprule.c
+++ b/ip/iprule.c
@@ -50,7 +50,7 @@ static void usage(void)
 int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 {
 	FILE *fp = (FILE*)arg;
-	struct rtmsg *r = NLMSG_DATA(n);
+	struct fib_rule_hdr *frh = NLMSG_DATA(n);
 	int len = n->nlmsg_len;
 	int host_len = -1;
 	__u32 table;
@@ -61,13 +61,13 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 	if (n->nlmsg_type != RTM_NEWRULE && n->nlmsg_type != RTM_DELRULE)
 		return 0;
 
-	len -= NLMSG_LENGTH(sizeof(*r));
+	len -= NLMSG_LENGTH(sizeof(*frh));
 	if (len < 0)
 		return -1;
 
-	parse_rtattr(tb, FRA_MAX, RTM_RTA(r), len);
+	parse_rtattr(tb, FRA_MAX, RTM_RTA(frh), len);
 
-	host_len = af_bit_len(r->rtm_family);
+	host_len = af_bit_len(frh->family);
 
 	if (n->nlmsg_type == RTM_DELRULE)
 		fprintf(fp, "Deleted ");
@@ -77,51 +77,51 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 	else
 		fprintf(fp, "0:\t");
 
-	if (r->rtm_flags & FIB_RULE_INVERT)
+	if (frh->flags & FIB_RULE_INVERT)
 		fprintf(fp, "not ");
 
 	if (tb[FRA_SRC]) {
-		if (r->rtm_src_len != host_len) {
-			fprintf(fp, "from %s/%u ", rt_addr_n2a(r->rtm_family,
+		if (frh->src_len != host_len) {
+			fprintf(fp, "from %s/%u ", rt_addr_n2a(frh->family,
 						       RTA_PAYLOAD(tb[FRA_SRC]),
 						       RTA_DATA(tb[FRA_SRC]),
 						       abuf, sizeof(abuf)),
-				r->rtm_src_len
+				frh->src_len
 				);
 		} else {
-			fprintf(fp, "from %s ", format_host(r->rtm_family,
+			fprintf(fp, "from %s ", format_host(frh->family,
 						       RTA_PAYLOAD(tb[FRA_SRC]),
 						       RTA_DATA(tb[FRA_SRC]),
 						       abuf, sizeof(abuf))
 				);
 		}
-	} else if (r->rtm_src_len) {
-		fprintf(fp, "from 0/%d ", r->rtm_src_len);
+	} else if (frh->src_len) {
+		fprintf(fp, "from 0/%d ", frh->src_len);
 	} else {
 		fprintf(fp, "from all ");
 	}
 
 	if (tb[FRA_DST]) {
-		if (r->rtm_dst_len != host_len) {
-			fprintf(fp, "to %s/%u ", rt_addr_n2a(r->rtm_family,
+		if (frh->dst_len != host_len) {
+			fprintf(fp, "to %s/%u ", rt_addr_n2a(frh->family,
 						       RTA_PAYLOAD(tb[FRA_DST]),
 						       RTA_DATA(tb[FRA_DST]),
 						       abuf, sizeof(abuf)),
-				r->rtm_dst_len
+				frh->dst_len
 				);
 		} else {
-			fprintf(fp, "to %s ", format_host(r->rtm_family,
+			fprintf(fp, "to %s ", format_host(frh->family,
 						       RTA_PAYLOAD(tb[FRA_DST]),
 						       RTA_DATA(tb[FRA_DST]),
 						       abuf, sizeof(abuf)));
 		}
-	} else if (r->rtm_dst_len) {
-		fprintf(fp, "to 0/%d ", r->rtm_dst_len);
+	} else if (frh->dst_len) {
+		fprintf(fp, "to 0/%d ", frh->dst_len);
 	}
 
-	if (r->rtm_tos) {
+	if (frh->tos) {
 		SPRINT_BUF(b1);
-		fprintf(fp, "tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
+		fprintf(fp, "tos %s ", rtnl_dsfield_n2a(frh->tos, b1, sizeof(b1)));
 	}
 
 	if (tb[FRA_FWMARK] || tb[FRA_FWMASK]) {
@@ -139,13 +139,13 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 
 	if (tb[FRA_IFNAME]) {
 		fprintf(fp, "iif %s ", rta_getattr_str(tb[FRA_IFNAME]));
-		if (r->rtm_flags & FIB_RULE_IIF_DETACHED)
+		if (frh->flags & FIB_RULE_IIF_DETACHED)
 			fprintf(fp, "[detached] ");
 	}
 
 	if (tb[FRA_OIFNAME]) {
 		fprintf(fp, "oif %s ", rta_getattr_str(tb[FRA_OIFNAME]));
-		if (r->rtm_flags & FIB_RULE_OIF_DETACHED)
+		if (frh->flags & FIB_RULE_OIF_DETACHED)
 			fprintf(fp, "[detached] ");
 	}
 
@@ -154,7 +154,13 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 			fprintf(fp, "lookup [l3mdev-table] ");
 	}
 
-	table = rtm_get_table(r, tb);
+	/*
+	 * struct fib_rule_hdr and struct rtmsg
+	 * were intentionally the same.  Since
+	 * the table is the rtm_table, just call
+	 * it.
+	 */
+	table = rtm_get_table((struct rtmsg *)frh, tb);
 	if (table) {
 		fprintf(fp, "lookup %s ", rtnl_rttable_n2a(table, b1, sizeof(b1)));
 
@@ -185,27 +191,27 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 			rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
 	}
 
-	if (r->rtm_type == RTN_NAT) {
+	if (frh->action == RTN_NAT) {
 		if (tb[RTA_GATEWAY]) {
 			fprintf(fp, "map-to %s ",
-				format_host(r->rtm_family,
+				format_host(frh->family,
 					    RTA_PAYLOAD(tb[RTA_GATEWAY]),
 					    RTA_DATA(tb[RTA_GATEWAY]),
 					    abuf, sizeof(abuf)));
 		} else
 			fprintf(fp, "masquerade");
-	} else if (r->rtm_type == FR_ACT_GOTO) {
+	} else if (frh->action == FR_ACT_GOTO) {
 		fprintf(fp, "goto ");
 		if (tb[FRA_GOTO])
 			fprintf(fp, "%u", rta_getattr_u32(tb[FRA_GOTO]));
 		else
 			fprintf(fp, "none");
-		if (r->rtm_flags & FIB_RULE_UNRESOLVED)
+		if (frh->flags & FIB_RULE_UNRESOLVED)
 			fprintf(fp, " [unresolved]");
-	} else if (r->rtm_type == FR_ACT_NOP)
+	} else if (frh->action == FR_ACT_NOP)
 		fprintf(fp, "nop");
-	else if (r->rtm_type != RTN_UNICAST)
-		fprintf(fp, "%s", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));
+	else if (frh->action != RTN_UNICAST)
+		fprintf(fp, "%s", rtnl_rtntype_n2a(frh->action, b1, sizeof(b1)));
 
 	fprintf(fp, "\n");
 	fflush(fp);
@@ -245,7 +251,7 @@ static int iprule_modify(int cmd, int argc, char **argv)
 	__u32 tid = 0;
 	struct {
 		struct nlmsghdr	n;
-		struct rtmsg		r;
+		struct fib_rule_hdr frh;
 		char  			buf[1024];
 	} req;
 
@@ -254,32 +260,31 @@ static int iprule_modify(int cmd, int argc, char **argv)
 	req.n.nlmsg_type = cmd;
 	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 	req.n.nlmsg_flags = NLM_F_REQUEST;
-	req.r.rtm_family = preferred_family;
-	req.r.rtm_protocol = RTPROT_BOOT;
-	req.r.rtm_scope = RT_SCOPE_UNIVERSE;
-	req.r.rtm_table = 0;
-	req.r.rtm_type = RTN_UNSPEC;
-	req.r.rtm_flags = 0;
+	req.frh.family = preferred_family;
+	req.frh.proto = RTPROT_BOOT;
+	req.frh.table = 0;
+	req.frh.action = RTN_UNSPEC;
+	req.frh.flags = 0;
 
 	if (cmd == RTM_NEWRULE) {
 		req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
-		req.r.rtm_type = RTN_UNICAST;
+		req.frh.action = RTN_UNICAST;
 	}
 
 	while (argc > 0) {
 		if (strcmp(*argv, "not") == 0) {
-			req.r.rtm_flags |= FIB_RULE_INVERT;
+			req.frh.flags |= FIB_RULE_INVERT;
 		} else if (strcmp(*argv, "from") == 0) {
 			inet_prefix dst;
 			NEXT_ARG();
-			get_prefix(&dst, *argv, req.r.rtm_family);
-			req.r.rtm_src_len = dst.bitlen;
+			get_prefix(&dst, *argv, req.frh.family);
+			req.frh.src_len = dst.bitlen;
 			addattr_l(&req.n, sizeof(req), FRA_SRC, &dst.data, dst.bytelen);
 		} else if (strcmp(*argv, "to") == 0) {
 			inet_prefix dst;
 			NEXT_ARG();
-			get_prefix(&dst, *argv, req.r.rtm_family);
-			req.r.rtm_dst_len = dst.bitlen;
+			get_prefix(&dst, *argv, req.frh.family);
+			req.frh.dst_len = dst.bitlen;
 			addattr_l(&req.n, sizeof(req), FRA_DST, &dst.data, dst.bytelen);
 		} else if (matches(*argv, "preference") == 0 ||
 			   matches(*argv, "order") == 0 ||
@@ -295,7 +300,7 @@ static int iprule_modify(int cmd, int argc, char **argv)
 			NEXT_ARG();
 			if (rtnl_dsfield_a2n(&tos, *argv))
 				invarg("TOS value is invalid\n", *argv);
-			req.r.rtm_tos = tos;
+			req.frh.tos = tos;
 		} else if (strcmp(*argv, "fwmark") == 0) {
 			char *slash;
 			__u32 fwmark, fwmask;
@@ -322,9 +327,9 @@ static int iprule_modify(int cmd, int argc, char **argv)
 			if (rtnl_rttable_a2n(&tid, *argv))
 				invarg("invalid table ID\n", *argv);
 			if (tid < 256)
-				req.r.rtm_table = tid;
+				req.frh.table = tid;
 			else {
-				req.r.rtm_table = RT_TABLE_UNSPEC;
+				req.frh.table = RT_TABLE_UNSPEC;
 				addattr32(&req.n, sizeof(req), FRA_TABLE, tid);
 			}
 			table_ok = 1;
@@ -358,7 +363,7 @@ static int iprule_modify(int cmd, int argc, char **argv)
 			NEXT_ARG();
 			fprintf(stderr, "Warning: route NAT is deprecated\n");
 			addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
-			req.r.rtm_type = RTN_NAT;
+			req.frh.action = RTN_NAT;
 		} else {
 			int type;
 
@@ -378,7 +383,7 @@ static int iprule_modify(int cmd, int argc, char **argv)
 				type = FR_ACT_NOP;
 			else if (rtnl_rtntype_a2n(&type, *argv))
 				invarg("Failed to parse rule type", *argv);
-			req.r.rtm_type = type;
+			req.frh.action = type;
 			table_ok = 1;
 		}
 		argc--;
@@ -391,11 +396,11 @@ static int iprule_modify(int cmd, int argc, char **argv)
 		return -EINVAL;
 	}
 
-	if (req.r.rtm_family == AF_UNSPEC)
-		req.r.rtm_family = AF_INET;
+	if (req.frh.family == AF_UNSPEC)
+		req.frh.family = AF_INET;
 
 	if (!table_ok && cmd == RTM_NEWRULE)
-		req.r.rtm_table = RT_TABLE_MAIN;
+		req.frh.table = RT_TABLE_MAIN;
 
 	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)
 		return -2;
-- 
2.14.3