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passt: Introduce packet batching mechanism

Browse source 
Receive packets in batches from AF_UNIX, check if they can be sent
with a single syscall, and batch them up with sendmmsg() in case.

A bit rudimentary, currently only implemented for UDP, but it seems
to work.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2021-04-22 13:39:36 +02:00
parent 5b0c88d4ef
commit 1f7cf04d34
8 changed files with 337 additions and 122 deletions

44
tcp.c
View file

@ -583,7 +583,7 @@ static int tcp_sock_hash_match(struct tcp_conn *conn, int af, void *addr,
static unsigned int tcp_sock_hash(struct ctx *c, int af, void *addr,
in_port_t tap_port, in_port_t sock_port)
{
uint64_t b;
uint64_t b = 0;
if (af == AF_INET) {
struct {
@ -853,7 +853,7 @@ static uint32_t tcp_seq_init(struct ctx *c, int af, void *addr,
in_port_t dstport, in_port_t srcport)
{
struct timespec ts = { 0 };
uint32_t ns, seq;
uint32_t ns, seq = 0;
clock_gettime(CLOCK_MONOTONIC, &ts);
@ -1186,31 +1186,39 @@ out:
* tcp_tap_handler() - Handle packets from tap and state transitions
* @c: Execution context
* @af: Address family, AF_INET or AF_INET6
* @in: Input buffer
* @len: Length, including TCP header
* @msg: Input messages
* @count: Message count
*
* Return: count of consumed packets
*/
void tcp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
int tcp_tap_handler(struct ctx *c, int af, void *addr,
struct tap_msg *msg, int count)
{
struct tcphdr *th = (struct tcphdr *)in;
/* TODO: Implement message batching for TCP */
struct tcphdr *th = (struct tcphdr *)msg[0].l4h;
size_t len = msg[0].l4_len;
size_t off, skip = 0;
int s, ws;
(void)count;
if (len < sizeof(*th))
return;
return 1;
off = th->doff * 4;
if (off < sizeof(*th) || off > len)
return;
return 1;
if ((s = tcp_sock_hash_lookup(c, af, addr, th->source, th->dest)) < 0) {
if (th->syn)
tcp_conn_from_tap(c, af, addr, th, len);
return;
return 1;
}
if (th->rst) {
tcp_close_and_epoll_del(c, s);
return;
return 1;
}
tcp_clamp_window(s, th, len, th->syn && th->ack);
@ -1224,7 +1232,7 @@ void tcp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
case SOCK_SYN_SENT:
if (!th->syn || !th->ack) {
tcp_rst(c, s);
return;
return 1;
}
tc[s].mss_guest = tcp_opt_get(th, len, OPT_MSS, NULL, NULL);
@ -1234,12 +1242,12 @@ void tcp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
ws = tcp_opt_get(th, len, OPT_WS, NULL, NULL);
if (ws > MAX_WS) {
if (tcp_send_to_tap(c, s, RST, NULL, 0))
return;
return 1;
tc[s].seq_to_tap = 0;
tc[s].ws_allowed = 0;
tcp_send_to_tap(c, s, SYN, NULL, 0);
return;
return 1;
}
/* info.tcpi_bytes_acked already includes one byte for SYN, but
@ -1261,7 +1269,7 @@ void tcp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
if (!th->ack) {
tcp_rst(c, s);
return;
return 1;
}
tcp_set_state(s, ESTABLISHED);
@ -1294,7 +1302,8 @@ void tcp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
}
if (skip < len - off &&
tcp_send_to_sock(c, s, in + off + skip, len - off - skip,
tcp_send_to_sock(c, s,
msg[0].l4h + off + skip, len - off - skip,
th->psh ? 0 : MSG_MORE))
break;
@ -1311,7 +1320,8 @@ void tcp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
tcp_sock_consume(s, ntohl(th->ack_seq));
if (skip < len - off &&
tcp_send_to_sock(c, s, in + off + skip, len - off - skip,
tcp_send_to_sock(c, s,
msg[0].l4h + off + skip, len - off - skip,
th->psh ? 0 : MSG_MORE))
break;
@ -1331,6 +1341,8 @@ void tcp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
case CLOSED: /* ;) */
break;
}
return 1;
}
/**