[lib] Switch Fletcher checksum back to old ospfd version
* lib/checksum.c: (fletcher_checksum) Switch the second phase of the checksum
back to the old ospfd logic.
The isisd-derived version:
a) is very hard to follow
b) had some kind of subtle bug that caused it be wrong when c0=0 and c1=254
(potentially fixable by doing the mods before adjusting x and y)
Additionally:
- explicitely cast expressions using non-internal variables to int, to ensure
the result is signed.
- defensively change the length argument to 'size_t', to ensure the code
works with that argument being unsigned..
Thanks to Joakim Tjernlund for the investigative work into this bug.
* tests/test-checksum.c: new file to exercise the checksum code.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c93fa08..4ab507b 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -6,7 +6,7 @@
noinst_PROGRAMS = testsig testbuffer testmemory heavy heavywq heavythread \
aspathtest testprivs teststream testbgpcap ecommtest \
- testbgpmpattr
+ testbgpmpattr testchecksum
testsig_SOURCES = test-sig.c
testbuffer_SOURCES = test-buffer.c
@@ -20,6 +20,7 @@
testbgpcap_SOURCES = bgp_capability_test.c
ecommtest_SOURCES = ecommunity_test.c
testbgpmpattr_SOURCES = bgp_mp_attr_test.c
+testchecksum_SOURCES = test-checksum.c
testsig_LDADD = ../lib/libzebra.la @LIBCAP@
testbuffer_LDADD = ../lib/libzebra.la @LIBCAP@
@@ -33,3 +34,4 @@
testbgpcap_LDADD = ../lib/libzebra.la @LIBCAP@ -lm ../bgpd/libbgp.a
ecommtest_LDADD = ../lib/libzebra.la @LIBCAP@ -lm ../bgpd/libbgp.a
testbgpmpattr_LDADD = ../lib/libzebra.la @LIBCAP@ -lm ../bgpd/libbgp.a
+testchecksum_LDADD = ../lib/libzebra.la @LIBCAP@