From 5eb3bc6d5594fccfff26329a26225f999e971652 Mon Sep 17 00:00:00 2001 From: "/C=EU/ST=EU/CN=Pablo Neira Ayuso/emailAddress=pablo@netfilter.org" Date: Mon, 16 Apr 2007 19:08:42 +0000 Subject: first step forward to merge conntrackd and conntrack into the same building chain --- src/checksum.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 src/checksum.c (limited to 'src/checksum.c') diff --git a/src/checksum.c b/src/checksum.c new file mode 100644 index 0000000..41866ff --- /dev/null +++ b/src/checksum.c @@ -0,0 +1,32 @@ +/* + * Extracted from RFC 1071 with some minor changes to fix compilation on GCC, + * this can probably be improved + * --pablo 11/feb/07 + */ + +#include + +unsigned short do_csum(const void *addr, unsigned int count) +{ + unsigned int sum = 0; + + /* checksumming disabled, just skip */ + if (CONFIG(flags) & DONT_CHECKSUM) + return 0; + + while(count > 1) { + /* This is the inner loop */ + sum += *((unsigned short *) addr++); + count -= 2; + } + + /* Add left-over byte, if any */ + if(count > 0) + sum += *((unsigned char *) addr); + + /* Fold 32-bit sum to 16 bits */ + while (sum>>16) + sum = (sum & 0xffff) + (sum >> 16); + + return ~sum; +} -- cgit v1.2.3