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| | /* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright (c) 2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#ifndef TAP_H
#define TAP_H
/** L2_MAX_LEN_PASTA - Maximum frame length for pasta mode (with L2 header)
*
* The kernel tuntap device imposes a maximum frame size of 65535 including
* 'hard_header_len' (14 bytes for L2 Ethernet in the case of "tap" mode).
*/
#define L2_MAX_LEN_PASTA USHRT_MAX
/** L2_MAX_LEN_PASST - Maximum frame length for passt mode (with L2 header)
*
* The only structural limit the Qemu socket protocol imposes on frames is
* (2^32-1) bytes, but that would be ludicrously long in practice. For now,
* limit it somewhat arbitrarily to 65535 bytes. FIXME: Work out an appropriate
* limit with more precision.
*/
#define L2_MAX_LEN_PASST USHRT_MAX
/** L2_MAX_LEN_VU - Maximum frame length for vhost-user mode (with L2 header)
*
* VU allows multiple buffers per frame, each of which can be quite large, so
* the inherent frame size limit is rather large. Much larger than is actually
* useful for IP. For now limit arbitrarily to 65535 bytes. FIXME: Work out an
* appropriate limit with more precision.
*/
#define L2_MAX_LEN_VU USHRT_MAX
struct udphdr;
/**
* struct tap_hdr - tap backend specific headers
* @vnet_len: Frame length (for qemu socket transport)
*/
struct tap_hdr {
uint32_t vnet_len;
} __attribute__((packed));
/**
* tap_hdr_iov() - struct iovec for a tap header
* @c: Execution context
* @taph: Pointer to tap specific header buffer
*
* Returns: A struct iovec covering the correct portion of @taph to use as the
* tap specific header in the current configuration.
*/
static inline struct iovec tap_hdr_iov(const struct ctx *c,
struct tap_hdr *thdr)
{
return (struct iovec){
.iov_base = thdr,
.iov_len = c->mode == MODE_PASST ? sizeof(*thdr) : 0,
};
}
/**
* tap_hdr_update() - Update the tap specific header for a frame
* @taph: Tap specific header buffer to update
* @l2len: Frame length (including L2 headers)
*/
static inline void tap_hdr_update(struct tap_hdr *thdr, size_t l2len)
{
if (thdr)
thdr->vnet_len = htonl(l2len);
}
unsigned long tap_l2_max_len(const struct ctx *c);
void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t proto);
void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src,
struct in_addr dst, size_t l4len, uint8_t proto);
void *tap_push_uh4(struct udphdr *uh, struct in_addr src, in_port_t sport,
struct in_addr dst, in_port_t dport,
const void *in, size_t dlen);
void *tap_push_uh6(struct udphdr *uh,
const struct in6_addr *src, in_port_t sport,
const struct in6_addr *dst, in_port_t dport,
void *in, size_t dlen);
void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src,
struct in_addr dst, size_t l4len, uint8_t proto);
void *tap_push_ip6h(struct ipv6hdr *ip6h,
const struct in6_addr *src,
const struct in6_addr *dst,
size_t l4len, uint8_t proto, uint32_t flow);
void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
struct in_addr dst, in_port_t dport,
const void *in, size_t dlen);
void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct in_addr dst,
const void *in, size_t l4len);
const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
const struct in6_addr *src);
void *tap_push_ip6h(struct ipv6hdr *ip6h,
const struct in6_addr *src, const struct in6_addr *dst,
size_t l4len, uint8_t proto, uint32_t flow);
void tap_udp6_send(const struct ctx *c,
const struct in6_addr *src, in_port_t sport,
const struct in6_addr *dst, in_port_t dport,
uint32_t flow, void *in, size_t dlen);
void tap_icmp6_send(const struct ctx *c,
const struct in6_addr *src, const struct in6_addr *dst,
const void *in, size_t l4len);
void tap_send_single(const struct ctx *c, const void *data, size_t l2len);
size_t tap_send_frames(const struct ctx *c, const struct iovec *iov,
size_t bufs_per_frame, size_t nframes);
void eth_update_mac(struct ethhdr *eh,
const unsigned char *eth_d, const unsigned char *eth_s);
void tap_listen_handler(struct ctx *c, uint32_t events);
void tap_handler_pasta(struct ctx *c, uint32_t events,
const struct timespec *now);
void tap_handler_passt(struct ctx *c, uint32_t events,
const struct timespec *now);
int tap_sock_unix_open(char *sock_path);
void tap_sock_reset(struct ctx *c);
void tap_sock_update_pool(void *base, size_t size);
void tap_backend_init(struct ctx *c);
void tap_flush_pools(void);
void tap_handler(struct ctx *c, const struct timespec *now);
void tap_add_packet(struct ctx *c, ssize_t l2len, char *p);
#endif /* TAP_H */
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