From 64a0ba3b272dd9ee175e0c6256a6d0cb1733599b Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Wed, 21 Jul 2021 12:01:04 +0200 Subject: udp: Introduce recvmmsg()/sendmmsg(), zero-copy path from socket Packets are received directly onto pre-cooked, static buffers for IPv4 (with partial checksum pre-calculation) and IPv6 frames, with pre-filled Ethernet addresses and, partially, IP headers, and sent out from the same buffers with sendmmsg(), for both passt and pasta (non-local traffic only) modes. Signed-off-by: Stefano Brivio --- util.c | 40 ++++++++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 14 deletions(-) (limited to 'util.c') diff --git a/util.c b/util.c index 1372eec..4d4661a 100644 --- a/util.c +++ b/util.c @@ -76,6 +76,29 @@ logfn(info, LOG_INFO) logfn(debug, LOG_DEBUG) #endif +/** + * sum_16b() - Calculate sum of 16-bit words + * @buf: Input buffer + * @len: Buffer length + * + * Return: 32-bit sum of 16-bit words +*/ +uint32_t sum_16b(void *buf, size_t len) +{ + uint32_t sum = 0; + uint16_t *p = buf; + size_t len1 = len / 2; + size_t off; + + for (off = 0; off < len1; off++, p++) + sum += *p; + + if (len % 2) + sum += *p & 0xff; + + return sum; +} + /** * csum_fold() - Fold long sum for IP and TCP checksum * @sum: Original long sum @@ -91,7 +114,7 @@ uint16_t csum_fold(uint32_t sum) } /** - * csum_ipv4() - Calculate IPv4 checksum + * csum_ip4() - Calculate IPv4 checksum * @buf: Packet buffer, L3 headers * @len: Total L3 packet length * @@ -99,22 +122,11 @@ uint16_t csum_fold(uint32_t sum) */ uint16_t csum_ip4(void *buf, size_t len) { - uint32_t sum = 0; - uint16_t *p = buf; - size_t len1 = len / 2; - size_t off; - - for (off = 0; off < len1; off++, p++) - sum += *p; - - if (len % 2) - sum += *p & 0xff; - - return ~csum_fold(sum); + return ~csum_fold(sum_16b(buf, len)); } /** - * csum_ipv4() - Calculate TCP checksum for IPv4 and set in place + * csum_tcp4() - Calculate TCP checksum for IPv4 and set in place * @iph: Packet buffer, IP header */ void csum_tcp4(struct iphdr *iph) -- cgit v1.2.3