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passt/tcp.h
David Gibson 043a70b885 tcp, tap: Correctly advance through packets in tcp_tap_handler()
In both tap4_handler() and tap6_handler(), once we've sorted incoming l3
packets into "sequences", we then step through all the packets in each TCP
sequence calling tcp_tap_handler().  Or so it appears.

In fact, tcp_tap_handler() doesn't take an index and always looks at packet
0 of the sequence, except when it calls tcp_data_from_tap() to process
data packets.  It appears to be written with the idea that the struct pool
is a queue, from which it consumes packets as it processes them, but that's
not how the pool data structure works - they are more like an array of
packets.

We only get away with this, because setup packets for TCP tend to come in
separate batches (because we need to reply in between) and so we only get
a bunch of packets for the same connection together when they're data
packets (tcp_data_from_tap() has its own loop through packets).

Correct this by adding an index parameter to tcp_tap_handler() and altering
the loops in tap.c to step through the pool properly.

Link: https://bugs.passt.top/show_bug.cgi?id=68
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2023-09-08 09:15:46 +02:00

79 lines
2.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright (c) 2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#ifndef TCP_H
#define TCP_H
#define TCP_TIMER_INTERVAL 1000 /* ms */
#define TCP_CONN_INDEX_BITS 17 /* 128k - 1 */
#define TCP_MAX_CONNS MAX_FROM_BITS(TCP_CONN_INDEX_BITS)
struct ctx;
void tcp_timer_handler(struct ctx *c, union epoll_ref ref);
void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
const struct timespec *now);
void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events);
int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
const struct pool *p, int idx, const struct timespec *now);
int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
const char *ifname, in_port_t port);
int tcp_init(struct ctx *c);
void tcp_timer(struct ctx *c, const struct timespec *ts);
void tcp_defer_handler(struct ctx *c);
void tcp_sock_set_bufsize(const struct ctx *c, int s);
void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s);
/**
* union tcp_epoll_ref - epoll reference portion for TCP connections
* @index: Index of connection in table
* @u32: Opaque u32 value of reference
*/
union tcp_epoll_ref {
uint32_t index:20;
uint32_t u32;
};
/**
* union tcp_listen_epoll_ref - epoll reference portion for TCP listening
* @port: Port number we're forwarding *to* (listening port plus delta)
* @ns: True if listening within the pasta namespace
* @u32: Opaque u32 value of reference
*/
union tcp_listen_epoll_ref {
struct {
in_port_t port;
bool ns;
};
uint32_t u32;
};
/**
* struct tcp_ctx - Execution context for TCP routines
* @hash_secret: 128-bit secret for hash functions, ISN and hash table
* @conn_count: Count of total connections in connection table
* @port_to_tap: Ports bound host-side, packets to tap or spliced
* @fwd_in: Port forwarding configuration for inbound packets
* @fwd_out: Port forwarding configuration for outbound packets
* @timer_run: Timestamp of most recent timer run
* @kernel_snd_wnd: Kernel reports sending window (with commit 8f7baad7f035)
* @pipe_size: Size of pipes for spliced connections
*/
struct tcp_ctx {
uint64_t hash_secret[2];
int conn_count;
struct port_fwd fwd_in;
struct port_fwd fwd_out;
struct timespec timer_run;
#ifdef HAS_SND_WND
int kernel_snd_wnd;
#endif
size_t pipe_size;
};
#endif /* TCP_H */