diff options
Diffstat (limited to 'tap.h')
| -rw-r--r-- | tap.h | 47 |
1 files changed, 46 insertions, 1 deletions
@@ -6,7 +6,32 @@ #ifndef TAP_H #define TAP_H -#define ETH_HDR_INIT(proto) { .h_proto = htons_constant(proto) } +/** 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) + * + * vhost-user 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 @@ -44,6 +69,23 @@ static inline void tap_hdr_update(struct tap_hdr *thdr, size_t l2len) 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); @@ -51,6 +93,9 @@ 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, |