Subject: [PATCH iproute2] ip: add support for more MPLS labels

From: David Ahern <[email-masked]>
Date: Sat, 13 May 2017 19:27:02 -0600

Kernel now supports up to 30 labels but not defined as part of the uapi.
iproute2 handles up to 8 labels but in a non-consistent way. Update ip
to handle more labels, but in a more programmatic way.

For the MPLS address family, the data field in inet_prefix is used for
labels.  Increase that field to 64 u32's -- 64 as nothing more than a
convenient power of 2 number.

Update mpls_pton to take the length of the address field, convert that
length to number of labels and add better error handling to the parsing
of the user supplied string.

Signed-off-by: David Ahern <[email-masked]>
---
 include/utils.h |  7 ++-----
 lib/mpls_pton.c | 11 +++++++----
 lib/utils.c     |  7 +++++--
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/include/utils.h b/include/utils.h
index 8c12e1e2a60c..bfbc9e6dff55 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -61,7 +61,7 @@ typedef struct
 	__s16 bitlen;
 	/* These next two fields match rtvia */
 	__u16 family;
-	__u32 data[8];
+	__u32 data[64];
 } inet_prefix;
 
 #define PREFIXLEN_SPECIFIED 1
@@ -88,9 +88,6 @@ struct ipx_addr {
 # define AF_MPLS 28
 #endif
 
-/* Maximum number of labels the mpls helpers support */
-#define MPLS_MAX_LABELS 8
-
 __u32 get_addr32(const char *name);
 int get_addr_1(inet_prefix *dst, const char *arg, int family);
 int get_prefix_1(inet_prefix *dst, char *arg, int family);
@@ -155,7 +152,7 @@ const char *ipx_ntop(int af, const void *addr, char *str, size_t len);
 int ipx_pton(int af, const char *src, void *addr);
 
 const char *mpls_ntop(int af, const void *addr, char *str, size_t len);
-int mpls_pton(int af, const char *src, void *addr);
+int mpls_pton(int af, const char *src, void *addr, size_t alen);
 
 extern int __iproute2_hz_internal;
 int __get_hz(void);
diff --git a/lib/mpls_pton.c b/lib/mpls_pton.c
index bd448cfcf14a..6d2e6a69436a 100644
--- a/lib/mpls_pton.c
+++ b/lib/mpls_pton.c
@@ -7,12 +7,13 @@
 #include "utils.h"

-static int mpls_pton1(const char *name, struct mpls_label *addr)
+static int mpls_pton1(const char *name, struct mpls_label *addr,
+		      unsigned int maxlabels)
 {
 	char *endp;
 	unsigned count;
 
-	for (count = 0; count < MPLS_MAX_LABELS; count++) {
+	for (count = 0; count < maxlabels; count++) {
 		unsigned long label;
 
 		label = strtoul(name, &endp, 0);
@@ -37,17 +38,19 @@ static int mpls_pton1(const char *name, struct mpls_label *addr)
 		addr += 1;
 	}
 	/* The address was too long */
+	fprintf(stderr, "Error: too many labels.\n");
 	return 0;
 }
 
-int mpls_pton(int af, const char *src, void *addr)
+int mpls_pton(int af, const char *src, void *addr, size_t alen)
 {
+	unsigned int maxlabels = alen / sizeof(struct mpls_label);
 	int err;
 
 	switch(af) {
 	case AF_MPLS:
 		errno = 0;
-		err = mpls_pton1(src, (struct mpls_label *)addr);
+		err = mpls_pton1(src, (struct mpls_label *)addr, maxlabels);
 		break;
 	default:
 		errno = EAFNOSUPPORT;
diff --git a/lib/utils.c b/lib/utils.c
index 6d5642f4f1f3..e77bd302530b 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -518,15 +518,18 @@ int get_addr_1(inet_prefix *addr, const char *name, int family)
 	}
 
 	if (family == AF_MPLS) {
+		unsigned int maxlabels;
 		int i;
 
 		addr->family = AF_MPLS;
-		if (mpls_pton(AF_MPLS, name, addr->data) <= 0)
+		if (mpls_pton(AF_MPLS, name, addr->data,
+			      sizeof(addr->data)) <= 0)
 			return -1;
 		addr->bytelen = 4;
 		addr->bitlen = 20;
 		/* How many bytes do I need? */
-		for (i = 0; i < 8; i++) {
+		maxlabels = sizeof(addr->data) / sizeof(struct mpls_label);
+		for (i = 0; i < maxlabels; i++) {
 			if (ntohl(addr->data[i]) & MPLS_LS_S_MASK) {
 				addr->bytelen = (i + 1)*4;
 				break;
-- 
2.11.0 (Apple Git-81)