netfilter: xtables: change matches to return error code

The following semantic patch does part of the transformation:
// <smpl>
@ rule1 @
struct xt_match ops;
identifier check;
@@
 ops.checkentry = check;

@@
identifier rule1.check;
@@
 check(...) { <...
-return true;
+return 0;
 ...> }

@@
identifier rule1.check;
@@
 check(...) { <...
-return false;
+return -EINVAL;
 ...> }
// </smpl>

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

net/ipv6/netfilter/ip6_tables.c

@@ -2214,7 +2214,7 @@ static int icmp6_checkentry(const struct xt_mtchk_param *par)
 	const struct ip6t_icmp *icmpinfo = par->matchinfo;
 
 	/* Must specify no unknown invflags */
-	return !(icmpinfo->invflags & ~IP6T_ICMP_INV);
+	return (icmpinfo->invflags & ~IP6T_ICMP_INV) ? -EINVAL : 0;
 }
 
 /* The built-in targets: standard (NULL) and error. */

net/ipv6/netfilter/ip6t_ah.c

@@ -93,9 +93,9 @@ static int ah_mt6_check(const struct xt_mtchk_param *par)
 
 	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
 		pr_debug("unknown flags %X\n", ahinfo->invflags);
-		return false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static struct xt_match ah_mt6_reg __read_mostly = {

net/ipv6/netfilter/ip6t_frag.c

@@ -108,9 +108,9 @@ static int frag_mt6_check(const struct xt_mtchk_param *par)
 
 	if (fraginfo->invflags & ~IP6T_FRAG_INV_MASK) {
 		pr_debug("unknown flags %X\n", fraginfo->invflags);
-		return false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static struct xt_match frag_mt6_reg __read_mostly = {

net/ipv6/netfilter/ip6t_hbh.c

@@ -170,15 +170,15 @@ static int hbh_mt6_check(const struct xt_mtchk_param *par)
 
 	if (optsinfo->invflags & ~IP6T_OPTS_INV_MASK) {
 		pr_debug("unknown flags %X\n", optsinfo->invflags);
-		return false;
+		return -EINVAL;
 	}
 
 	if (optsinfo->flags & IP6T_OPTS_NSTRICT) {
 		pr_debug("Not strict - not implemented");
-		return false;
+		return -EINVAL;
 	}
 
-	return true;
+	return 0;
 }
 
 static struct xt_match hbh_mt6_reg[] __read_mostly = {

net/ipv6/netfilter/ip6t_ipv6header.c

@@ -125,9 +125,9 @@ static int ipv6header_mt6_check(const struct xt_mtchk_param *par)
 	/* invflags is 0 or 0xff in hard mode */
 	if ((!info->modeflag) && info->invflags != 0x00 &&
 	    info->invflags != 0xFF)
-		return false;
+		return -EINVAL;
 
-	return true;
+	return 0;
 }
 
 static struct xt_match ipv6header_mt6_reg __read_mostly = {

net/ipv6/netfilter/ip6t_mh.c

@@ -67,7 +67,7 @@ static int mh_mt6_check(const struct xt_mtchk_param *par)
 	const struct ip6t_mh *mhinfo = par->matchinfo;
 
 	/* Must specify no unknown invflags */
-	return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);
+	return (mhinfo->invflags & ~IP6T_MH_INV_MASK) ? -EINVAL : 0;
 }
 
 static struct xt_match mh_mt6_reg __read_mostly = {

net/ipv6/netfilter/ip6t_rt.c

@@ -189,17 +189,17 @@ static int rt_mt6_check(const struct xt_mtchk_param *par)
 
 	if (rtinfo->invflags & ~IP6T_RT_INV_MASK) {
 		pr_debug("unknown flags %X\n", rtinfo->invflags);
-		return false;
+		return -EINVAL;
 	}
 	if ((rtinfo->flags & (IP6T_RT_RES | IP6T_RT_FST_MASK)) &&
 	    (!(rtinfo->flags & IP6T_RT_TYP) ||
 	     (rtinfo->rt_type != 0) ||
 	     (rtinfo->invflags & IP6T_RT_INV_TYP))) {
 		pr_debug("`--rt-type 0' required before `--rt-0-*'");
-		return false;
+		return -EINVAL;
 	}
 
-	return true;
+	return 0;
 }
 
 static struct xt_match rt_mt6_reg __read_mostly = {