From: Quentin Young <qlyoung@cumulusnetworks.com>
Date: Tue, 22 Jan 2019 22:39:47 +0000 (+0000)
Subject: lib: add internet checksum with pseudoheaders
X-Git-Tag: base_7.2~330^2~127
X-Git-Url: https://git.puffer.fish/?a=commitdiff_plain;h=17b48d7d1150ba4b4ee689a925f54b2a236b1d23;p=matthieu%2Ffrr.git

lib: add internet checksum with pseudoheaders

Add convenience functions to compute the Internet checksum of a data
block, including a pseudoheader.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
---

diff --git a/lib/checksum.c b/lib/checksum.c
index 18e3850474..3473370041 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -46,6 +46,24 @@ int /* return checksum in low-order 16 bits */
 	return (answer);
 }
 
+int in_cksum_with_ph4(struct ipv4_ph *ph, void *data, int nbytes)
+{
+	uint8_t dat[sizeof(struct ipv4_ph) + nbytes];
+
+	memcpy(dat, ph, sizeof(struct ipv4_ph));
+	memcpy(dat + sizeof(struct ipv4_ph), data, nbytes);
+	return in_cksum(dat, sizeof(dat));
+}
+
+int in_cksum_with_ph6(struct ipv6_ph *ph, void *data, int nbytes)
+{
+	uint8_t dat[sizeof(struct ipv6_ph) + nbytes];
+
+	memcpy(dat, ph, sizeof(struct ipv6_ph));
+	memcpy(dat + sizeof(struct ipv6_ph), data, nbytes);
+	return in_cksum(dat, sizeof(dat));
+}
+
 /* Fletcher Checksum -- Refer to RFC1008. */
 #define MODX                 4102U   /* 5802 should be fine */
 
diff --git a/lib/checksum.h b/lib/checksum.h
index 7d50371439..56771d4f24 100644
--- a/lib/checksum.h
+++ b/lib/checksum.h
@@ -1,8 +1,33 @@
+#include <stdint.h>
+#include <netinet/in.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-extern int in_cksum(void *, int);
+
+/* IPv4 pseudoheader */
+struct ipv4_ph {
+	struct in_addr src;
+	struct in_addr dst;
+	uint8_t rsvd;
+	uint8_t proto;
+	uint16_t len;
+} __attribute__((packed));
+
+/* IPv6 pseudoheader */
+struct ipv6_ph {
+	struct in6_addr src;
+	struct in6_addr dst;
+	uint32_t ulpl;
+	uint8_t zero[3];
+	uint8_t next_hdr;
+} __attribute__((packed));
+
+extern int in_cksum(void *data, int nbytes);
+extern int in_cksum_with_ph4(struct ipv4_ph *ph, void *data, int nbytes);
+extern int in_cksum_with_ph6(struct ipv6_ph *ph, void *data, int nbytes);
+
 #define FLETCHER_CHECKSUM_VALIDATE 0xffff
 extern uint16_t fletcher_checksum(uint8_t *, const size_t len,
 				  const uint16_t offset);