5566386f5f
At various points we need to track the lengths of a packet including or
excluding various different sets of headers. We don't always use the same
variable names for doing so. Worse in some places we use the same name
for different things: e.g. tcp_fill_headers[46]() use ip_len for the
length including the IP headers, but then tcp_send_flag() which calls it
uses it to mean the IP payload length only.
To improve clarity, standardise on these names:
dlen: L4 protocol payload length ("data length")
l4len: plen + length of L4 protocol header
l3len: l4len + length of IPv4/IPv6 header
l2len: l3len + length of L2 (ethernet) header
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
84 lines
2.7 KiB
C
84 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright (c) 2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#ifndef TAP_H
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#define TAP_H
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#define ETH_HDR_INIT(proto) { .h_proto = htons_constant(proto) }
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/**
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* struct tap_hdr - tap backend specific headers
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* @vnet_len: Frame length (for qemu socket transport)
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*/
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struct tap_hdr {
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uint32_t vnet_len;
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} __attribute__((packed));
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static inline size_t tap_hdr_len_(const struct ctx *c)
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{
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if (c->mode == MODE_PASST)
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return sizeof(struct tap_hdr);
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else
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return 0;
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}
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/**
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* tap_frame_base() - Find start of tap frame
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* @c: Execution context
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* @taph: Pointer to tap specific header buffer
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*
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* Returns: pointer to the start of tap frame - suitable for an
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* iov_base to be passed to tap_send_frames())
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*/
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static inline void *tap_frame_base(const struct ctx *c, struct tap_hdr *taph)
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{
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return (char *)(taph + 1) - tap_hdr_len_(c);
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}
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/**
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* tap_frame_len() - Finalize tap frame and return total length
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* @c: Execution context
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* @taph: Tap header to finalize
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* @l2len: L2 packet length (includes L2, excludes tap specific headers)
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*
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* Returns: length of the tap frame including tap specific headers - suitable
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* for an iov_len to be passed to tap_send_frames()
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*/
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static inline size_t tap_frame_len(const struct ctx *c, struct tap_hdr *taph,
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size_t l2len)
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{
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if (c->mode == MODE_PASST)
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taph->vnet_len = htonl(l2len);
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return l2len + tap_hdr_len_(c);
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}
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struct in_addr tap_ip4_daddr(const struct ctx *c);
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void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
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struct in_addr dst, in_port_t dport,
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const void *in, size_t dlen);
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void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct in_addr dst,
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const void *in, size_t l4len);
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const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
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const struct in6_addr *src);
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void tap_udp6_send(const struct ctx *c,
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const struct in6_addr *src, in_port_t sport,
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const struct in6_addr *dst, in_port_t dport,
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uint32_t flow, const void *in, size_t dlen);
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void tap_icmp6_send(const struct ctx *c,
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const struct in6_addr *src, const struct in6_addr *dst,
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const void *in, size_t l4len);
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void tap_send_single(const struct ctx *c, const void *data, size_t l2len);
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size_t tap_send_frames(const struct ctx *c, const struct iovec *iov,
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size_t bufs_per_frame, size_t nframes);
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void eth_update_mac(struct ethhdr *eh,
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const unsigned char *eth_d, const unsigned char *eth_s);
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void tap_listen_handler(struct ctx *c, uint32_t events);
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void tap_handler_pasta(struct ctx *c, uint32_t events,
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const struct timespec *now);
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void tap_handler_passt(struct ctx *c, uint32_t events,
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const struct timespec *now);
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void tap_sock_init(struct ctx *c);
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#endif /* TAP_H */
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