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tcp_splice: Helpers for converting from index to/from tcp_splice_conn

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Like we already have for non-spliced connections, create a CONN_IDX()
macro for looking up the index of spliced connection structures.  Change
the name of the array of spliced connections to be different from that for
non-spliced connections (even though they're in different modules).  This
will make subsequent changes a bit safer.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2022-11-17 16:58:42 +11:00 committed by Stefano Brivio
parent 60be7438fa
commit c6b822428a
1 changed files with 25 additions and 18 deletions
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43
tcp_splice.c
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@ -13,10 +13,11 @@
* DOC: Theory of Operation
*
*
* For local traffic directed to TCP ports configured for direct mapping between
* namespaces, packets are directly translated between L4 sockets using a pair
* of splice() syscalls. These connections are tracked in the @tc array of
* struct tcp_splice_conn, using these events:
* For local traffic directed to TCP ports configured for direct
* mapping between namespaces, packets are directly translated between
* L4 sockets using a pair of splice() syscalls. These connections are
* tracked in the @tc_splice array of struct tcp_splice_conn, using
* these events:
*
* - SPLICE_CONNECT: connection accepted, connecting to target
* - SPLICE_ESTABLISHED: connection to target established
@ -113,10 +114,11 @@ struct tcp_splice_conn {
#define CONN_V6(x) (x->flags & SOCK_V6)
#define CONN_V4(x) (!CONN_V6(x))
#define CONN_HAS(conn, set) ((conn->events & (set)) == (set))
#define CONN(index) (tc + (index))
#define CONN(index) (tc_splice + (index))
#define CONN_IDX(conn) ((conn) - tc_splice)
/* Spliced connections */
static struct tcp_splice_conn tc[TCP_SPLICE_MAX_CONNS];
static struct tcp_splice_conn tc_splice[TCP_SPLICE_MAX_CONNS];
/* Display strings for connection events */
static const char *tcp_splice_event_str[] __attribute((__unused__)) = {
@ -173,7 +175,7 @@ static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn,
conn->flags &= flag;
if (fls(~flag) >= 0) {
debug("TCP (spliced): index %li: %s dropped", conn - tc,
debug("TCP (spliced): index %li: %s dropped", CONN_IDX(conn),
tcp_splice_flag_str[fls(~flag)]);
}
} else {
@ -182,7 +184,7 @@ static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn,
conn->flags |= flag;
if (fls(flag) >= 0) {
debug("TCP (spliced): index %li: %s", conn - tc,
debug("TCP (spliced): index %li: %s", CONN_IDX(conn),
tcp_splice_flag_str[fls(flag)]);
}
}
@ -211,11 +213,11 @@ static int tcp_splice_epoll_ctl(const struct ctx *c,
int m = (conn->flags & IN_EPOLL) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
union epoll_ref ref_a = { .r.proto = IPPROTO_TCP, .r.s = conn->a,
.r.p.tcp.tcp.splice = 1,
.r.p.tcp.tcp.index = conn - tc,
.r.p.tcp.tcp.index = CONN_IDX(conn),
.r.p.tcp.tcp.v6 = CONN_V6(conn) };
union epoll_ref ref_b = { .r.proto = IPPROTO_TCP, .r.s = conn->b,
.r.p.tcp.tcp.splice = 1,
.r.p.tcp.tcp.index = conn - tc,
.r.p.tcp.tcp.index = CONN_IDX(conn),
.r.p.tcp.tcp.v6 = CONN_V6(conn) };
struct epoll_event ev_a = { .data.u64 = ref_a.u64 };
struct epoll_event ev_b = { .data.u64 = ref_b.u64 };
@ -257,7 +259,7 @@ static void conn_event_do(const struct ctx *c, struct tcp_splice_conn *conn,
conn->events &= event;
if (fls(~event) >= 0) {
debug("TCP (spliced): index %li, ~%s", conn - tc,
debug("TCP (spliced): index %li, ~%s", CONN_IDX(conn),
tcp_splice_event_str[fls(~event)]);
}
} else {
@ -266,7 +268,7 @@ static void conn_event_do(const struct ctx *c, struct tcp_splice_conn *conn,
conn->events |= event;
if (fls(event) >= 0) {
debug("TCP (spliced): index %li, %s", conn - tc,
debug("TCP (spliced): index %li, %s", CONN_IDX(conn),
tcp_splice_event_str[fls(event)]);
}
}
@ -292,8 +294,8 @@ static void tcp_table_splice_compact(struct ctx *c,
{
struct tcp_splice_conn *move;
if ((hole - tc) == --c->tcp.splice_conn_count) {
debug("TCP (spliced): index %li (max) removed", hole - tc);
if (CONN_IDX(hole) == --c->tcp.splice_conn_count) {
debug("TCP (spliced): index %li (max) removed", CONN_IDX(hole));
return;
}
@ -307,7 +309,8 @@ static void tcp_table_splice_compact(struct ctx *c,
move->pipe_b_a[0] = move->pipe_b_a[1] = -1;
move->flags = move->events = 0;
debug("TCP (spliced): index %li moved to %li", move - tc, hole - tc);
debug("TCP (spliced): index %li moved to %li",
CONN_IDX(move), CONN_IDX(hole));
tcp_splice_epoll_ctl(c, hole);
if (tcp_splice_epoll_ctl(c, hole))
conn_flag(c, hole, CLOSING);
@ -345,7 +348,7 @@ static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
conn->events = CLOSED;
conn->flags = 0;
debug("TCP (spliced): index %li, CLOSED", conn - tc);
debug("TCP (spliced): index %li, CLOSED", CONN_IDX(conn));
tcp_table_splice_compact(c, conn);
}
@ -872,7 +875,9 @@ void tcp_splice_timer(struct ctx *c)
{
struct tcp_splice_conn *conn;
for (conn = CONN(c->tcp.splice_conn_count - 1); conn >= tc; conn--) {
for (conn = CONN(c->tcp.splice_conn_count - 1);
conn >= tc_splice;
conn--) {
if (conn->flags & CLOSING) {
tcp_splice_destroy(c, conn);
return;
@ -918,7 +923,9 @@ void tcp_splice_defer_handler(struct ctx *c)
if (c->tcp.splice_conn_count < MIN(max_files / 6, max_conns))
return;
for (conn = CONN(c->tcp.splice_conn_count - 1); conn >= tc; conn--) {
for (conn = CONN(c->tcp.splice_conn_count - 1);
conn >= tc_splice;
conn--) {
if (conn->flags & CLOSING)
tcp_splice_destroy(c, conn);
}