From 4b3d38a0690988387fa4cef432ad96fe7ee32bf8 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 6 Jan 2023 11:43:17 +1100 Subject: tap: Add "tap headers" abstraction Currently both the TCP and UDP code need to deal in various places with the details of the L2 headers, and also the tap-specific "vnet_len" header. This makes abstracting the tap interface to new backends (e.g. vhost-user or tun) more difficult. To improve this abstraction, create a new 'tap_hdr' structure which represents both L2 (always Ethernet at the moment, but might be vary in future) and any additional tap specific headers (such as the qemu socket's vnet_len field). Provide helper functions and macros to initialize, update and use it. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tap.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'tap.c') diff --git a/tap.c b/tap.c index 558a734..d0dd72c 100644 --- a/tap.c +++ b/tap.c @@ -386,6 +386,21 @@ void tap_send_frames(struct ctx *c, const struct iovec *iov, size_t n) pcap_multiple(iov, n, sizeof(uint32_t)); } +/** + * tap_update_mac() - Update tap L2 header with new Ethernet addresses + * @taph: Tap headers to update + * @eth_d: Ethernet destination address, NULL if unchanged + * @eth_s: Ethernet source address, NULL if unchanged + */ +void tap_update_mac(struct tap_hdr *taph, + const unsigned char *eth_d, const unsigned char *eth_s) +{ + if (eth_d) + memcpy(taph->eh.h_dest, eth_d, sizeof(taph->eh.h_dest)); + if (eth_s) + memcpy(taph->eh.h_source, eth_s, sizeof(taph->eh.h_source)); +} + PACKET_POOL_DECL(pool_l4, UIO_MAXIOV, pkt_buf); /** -- cgit v1.2.3