commit 701d6ed7361c4554411f06079816784bc43d6df4
Author: Tobias Brunner <tobias@strongswan.org>
Date:   Wed Oct 22 19:41:40 2014 +0200

    chunk: Fix internet checksum calculation on big-endian systems
    
    ntohs() might be defined as noop (#define ntohs(x) (x)) so we have
    to manually shorten the negated value (gets promoted to an int).

diff --git a/src/libstrongswan/utils/chunk.c b/src/libstrongswan/utils/chunk.c
index 4b24b37..c4471be 100644
--- a/src/libstrongswan/utils/chunk.c
+++ b/src/libstrongswan/utils/chunk.c
@@ -992,7 +992,7 @@ u_int32_t chunk_hash_static(chunk_t chunk)
  */
 u_int16_t chunk_internet_checksum_inc(chunk_t data, u_int16_t checksum)
 {
-	u_int32_t sum = ntohs(~checksum);
+	u_int32_t sum = ntohs((u_int16_t)~checksum);
 
 	while (data.len > 1)
 	{

commit 1c70c6ed275c7701877dbf6322721af38ada2d68
Author: Tobias Brunner <tobias@strongswan.org>
Date:   Wed Oct 22 19:43:22 2014 +0200

    unit-tests: Fix internet checksum tests on big-endian systems
    
    We actually need to do a byte-swap, which ntohs() only does on
    little-endian systems.

diff --git a/src/libstrongswan/tests/suites/test_chunk.c b/src/libstrongswan/tests/suites/test_chunk.c
index d71e010..b5d2365 100644
--- a/src/libstrongswan/tests/suites/test_chunk.c
+++ b/src/libstrongswan/tests/suites/test_chunk.c
@@ -787,6 +787,11 @@ END_TEST
  * test for chunk_internet_checksum[_inc]()
  */
 
+static inline u_int16_t compensate_alignment(u_int16_t val)
+{
+	return ((val & 0xff) << 8) | (val >> 8);
+}
+
 START_TEST(test_chunk_internet_checksum)
 {
 	chunk_t chunk;
@@ -804,9 +809,9 @@ START_TEST(test_chunk_internet_checksum)
 
 	/* need to compensate for even/odd alignment */
 	sum = chunk_internet_checksum(chunk_create(chunk.ptr, 9));
-	sum = ntohs(sum);
+	sum = compensate_alignment(sum);
 	sum = chunk_internet_checksum_inc(chunk_create(chunk.ptr+9, 11), sum);
-	sum = ntohs(sum);
+	sum = compensate_alignment(sum);
 	ck_assert_int_eq(0x442e, ntohs(sum));
 
 	chunk = chunk_from_chars(0x45,0x00,0x00,0x30,0x44,0x22,0x40,0x00,0x80,0x06,
@@ -821,9 +826,9 @@ START_TEST(test_chunk_internet_checksum)
 
 	/* need to compensate for even/odd alignment */
 	sum = chunk_internet_checksum(chunk_create(chunk.ptr, 9));
-	sum = ntohs(sum);
+	sum = compensate_alignment(sum);
 	sum = chunk_internet_checksum_inc(chunk_create(chunk.ptr+9, 10), sum);
-	sum = ntohs(sum);
+	sum = compensate_alignment(sum);
 	ck_assert_int_eq(0x4459, ntohs(sum));
 }
 END_TEST