flow, tcp: Consolidate flow pointer<->index helpers

Both tcp.c and tcp_splice.c define CONN_IDX() variants to find the index
of their connection structures in the connection table, now become the
unified flow table.  We can easily combine these into a common helper.
While we're there, add some trickery for some additional type safety.

They also define their own CONN() versions, which aren't so easily combined
since they need to return different types, but we can have them use a
common helper.

In the process, we standardise on always using an unsigned type to store
the connection / flow index, which makes more sense.  tcp.c's conn_at_idx()
remains for now, but we change its parameter to unsigned to match.  That in
turn means we can remove a check for negative values from it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 33 insertions, 34 deletions

diff --git a/tcp.c b/tcp.c
index 93eee4f..33a7366 100644
--- a/tcp.c
+++ b/tcp.c
@@ -570,17 +570,16 @@ tcp6_l2_flags_buf[TCP_FRAMES_MEM];
 
 static unsigned int tcp6_l2_flags_buf_used;
 
-#define CONN(idx)		(&flowtab[(idx)].tcp)
-#define CONN_IDX(conn)		((union flow *)(conn) - flowtab)
+#define CONN(idx)		(&(FLOW(idx)->tcp))
 
 /** conn_at_idx() - Find a connection by index, if present
  * @idx:	Index of connection to lookup
  *
  * Return: pointer to connection, or NULL if @idx is out of bounds
  */
-static inline struct tcp_tap_conn *conn_at_idx(int idx)
+static inline struct tcp_tap_conn *conn_at_idx(unsigned idx)
 {
-	if ((idx < 0) || (idx >= FLOW_MAX))
+	if (idx >= FLOW_MAX)
 		return NULL;
 	ASSERT(CONN(idx)->f.type == FLOW_TCP);
 	return CONN(idx);
@@ -640,7 +639,7 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 {
 	int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 	union epoll_ref ref = { .type = EPOLL_TYPE_TCP, .fd = conn->sock,
-				.tcp.index = CONN_IDX(conn) };
+				.tcp.index = FLOW_IDX(conn) };
 	struct epoll_event ev = { .data.u64 = ref.u64 };
 
 	if (conn->events == CLOSED) {
@@ -661,7 +660,7 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 	if (conn->timer != -1) {
 		union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP_TIMER,
 					  .fd = conn->sock,
-					  .tcp.index = CONN_IDX(conn) };
+					  .tcp.index = FLOW_IDX(conn) };
 		struct epoll_event ev_t = { .data.u64 = ref_t.u64,
 					    .events = EPOLLIN | EPOLLET };
 
@@ -689,7 +688,7 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 	if (conn->timer == -1) {
 		union epoll_ref ref = { .type = EPOLL_TYPE_TCP_TIMER,
 					.fd = conn->sock,
-					.tcp.index = CONN_IDX(conn) };
+					.tcp.index = FLOW_IDX(conn) };
 		struct epoll_event ev = { .data.u64 = ref.u64,
 					  .events = EPOLLIN | EPOLLET };
 		int fd;
@@ -725,7 +724,7 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 		it.it_value.tv_sec = ACT_TIMEOUT;
 	}
 
-	debug("TCP: index %li, timer expires in %lu.%03lus", CONN_IDX(conn),
+	debug("TCP: index %u, timer expires in %lu.%03lus", FLOW_IDX(conn),
 	      it.it_value.tv_sec, it.it_value.tv_nsec / 1000 / 1000);
 
 	timerfd_settime(conn->timer, 0, &it, NULL);
@@ -748,7 +747,7 @@ static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
 
 		conn->flags &= flag;
 		if (flag_index >= 0) {
-			debug("TCP: index %li: %s dropped", CONN_IDX(conn),
+			debug("TCP: index %u: %s dropped", FLOW_IDX(conn),
 			      tcp_flag_str[flag_index]);
 		}
 	} else {
@@ -769,7 +768,7 @@ static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
 
 		conn->flags |= flag;
 		if (flag_index >= 0) {
-			debug("TCP: index %li: %s", CONN_IDX(conn),
+			debug("TCP: index %u: %s", FLOW_IDX(conn),
 			      tcp_flag_str[flag_index]);
 		}
 	}
@@ -819,12 +818,12 @@ static void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn,
 		new += 5;
 
 	if (prev != new) {
-		debug("TCP: index %li, %s: %s -> %s", CONN_IDX(conn),
+		debug("TCP: index %u, %s: %s -> %s", FLOW_IDX(conn),
 		      num == -1 	       ? "CLOSED" : tcp_event_str[num],
 		      prev == -1	       ? "CLOSED" : tcp_state_str[prev],
 		      (new == -1 || num == -1) ? "CLOSED" : tcp_state_str[new]);
 	} else {
-		debug("TCP: index %li, %s", CONN_IDX(conn),
+		debug("TCP: index %u, %s", FLOW_IDX(conn),
 		      num == -1 	       ? "CLOSED" : tcp_event_str[num]);
 	}
 
@@ -1204,11 +1203,11 @@ static void tcp_hash_insert(const struct ctx *c, struct tcp_tap_conn *conn)
 	int b;
 
 	b = tcp_hash(c, &conn->faddr, conn->eport, conn->fport);
-	conn->next_index = tc_hash[b] ? CONN_IDX(tc_hash[b]) : -1;
+	conn->next_index = tc_hash[b] ? FLOW_IDX(tc_hash[b]) : -1U;
 	tc_hash[b] = conn;
 
-	debug("TCP: hash table insert: index %li, sock %i, bucket: %i, next: "
-	      "%p", CONN_IDX(conn), conn->sock, b,
+	debug("TCP: hash table insert: index %u, sock %i, bucket: %i, next: "
+	      "%p", FLOW_IDX(conn), conn->sock, b,
 	      (void *)conn_at_idx(conn->next_index));
 }
 
@@ -1234,8 +1233,8 @@ static void tcp_hash_remove(const struct ctx *c,
 		}
 	}
 
-	debug("TCP: hash table remove: index %li, sock %i, bucket: %i, new: %p",
-	      CONN_IDX(conn), conn->sock, b,
+	debug("TCP: hash table remove: index %u, sock %i, bucket: %i, new: %p",
+	      FLOW_IDX(conn), conn->sock, b,
 	      (void *)(prev ? conn_at_idx(prev->next_index) : tc_hash[b]));
 }
 
@@ -1255,16 +1254,16 @@ static void tcp_tap_conn_update(const struct ctx *c, struct tcp_tap_conn *old,
 	     prev = entry, entry = conn_at_idx(entry->next_index)) {
 		if (entry == old) {
 			if (prev)
-				prev->next_index = CONN_IDX(new);
+				prev->next_index = FLOW_IDX(new);
 			else
 				tc_hash[b] = new;
 			break;
 		}
 	}
 
-	debug("TCP: hash table update: old index %li, new index %li, sock %i, "
+	debug("TCP: hash table update: old index %u, new index %u, sock %i, "
 	      "bucket: %i, old: %p, new: %p",
-	      CONN_IDX(old), CONN_IDX(new), new->sock, b,
+	      FLOW_IDX(old), FLOW_IDX(new), new->sock, b,
 	      (void *)old, (void *)new);
 
 	tcp_epoll_ctl(c, new);
@@ -1307,9 +1306,9 @@ void tcp_table_compact(struct ctx *c, union flow *hole)
 {
 	union flow *from;
 
-	if (CONN_IDX(hole) == --c->flow_count) {
-		debug("TCP: table compaction: maximum index was %li (%p)",
-		      CONN_IDX(hole), (void *)hole);
+	if (FLOW_IDX(hole) == --c->flow_count) {
+		debug("TCP: table compaction: maximum index was %u (%p)",
+		      FLOW_IDX(hole), (void *)hole);
 		memset(hole, 0, sizeof(*hole));
 		return;
 	}
@@ -1329,9 +1328,9 @@ void tcp_table_compact(struct ctx *c, union flow *hole)
 		    FLOW_TYPE(&from->f));
 	}
 
-	debug("TCP: table compaction (%s): old index %li, new index %li, "
+	debug("TCP: table compaction (%s): old index %u, new index %u, "
 	      "from: %p, to: %p",
-	      FLOW_TYPE(&from->f), CONN_IDX(from), CONN_IDX(hole),
+	      FLOW_TYPE(&from->f), FLOW_IDX(from), FLOW_IDX(hole),
 	      (void *)from, (void *)hole);
 
 	memset(from, 0, sizeof(*from));
@@ -1357,7 +1356,7 @@ static void tcp_conn_destroy(struct ctx *c, union flow *flow)
 static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
 #define tcp_rst(c, conn)						\
 	do {								\
-		debug("TCP: index %li, reset at %s:%i", CONN_IDX(conn), \
+		debug("TCP: index %u, reset at %s:%i", FLOW_IDX(conn),	\
 		      __func__, __LINE__);				\
 		tcp_rst_do(c, conn);					\
 	} while (0)
@@ -2580,8 +2579,8 @@ int tcp_tap_handler(struct ctx *c, uint8_t pif, int af,
 		return 1;
 	}
 
-	trace("TCP: packet length %zu from tap for index %lu",
-	      len, CONN_IDX(conn));
+	trace("TCP: packet length %zu from tap for index %u",
+	      len, FLOW_IDX(conn));
 
 	if (th->rst) {
 		conn_event(c, conn, CLOSED);
@@ -2821,17 +2820,17 @@ void tcp_timer_handler(struct ctx *c, union epoll_ref ref)
 		tcp_timer_ctl(c, conn);
 	} else if (conn->flags & ACK_FROM_TAP_DUE) {
 		if (!(conn->events & ESTABLISHED)) {
-			debug("TCP: index %li, handshake timeout", CONN_IDX(conn));
+			debug("TCP: index %u, handshake timeout", FLOW_IDX(conn));
 			tcp_rst(c, conn);
 		} else if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED)) {
-			debug("TCP: index %li, FIN timeout", CONN_IDX(conn));
+			debug("TCP: index %u, FIN timeout", FLOW_IDX(conn));
 			tcp_rst(c, conn);
 		} else if (conn->retrans == TCP_MAX_RETRANS) {
-			debug("TCP: index %li, retransmissions count exceeded",
-			      CONN_IDX(conn));
+			debug("TCP: index %u, retransmissions count exceeded",
+			      FLOW_IDX(conn));
 			tcp_rst(c, conn);
 		} else {
-			debug("TCP: index %li, ACK timeout, retry", CONN_IDX(conn));
+			debug("TCP: index %u, ACK timeout, retry", FLOW_IDX(conn));
 			conn->retrans++;
 			conn->seq_to_tap = conn->seq_ack_from_tap;
 			tcp_data_from_sock(c, conn);
@@ -2849,7 +2848,7 @@ void tcp_timer_handler(struct ctx *c, union epoll_ref ref)
 		 */
 		timerfd_settime(conn->timer, 0, &new, &old);
 		if (old.it_value.tv_sec == ACT_TIMEOUT) {
-			debug("TCP: index %li, activity timeout", CONN_IDX(conn));
+			debug("TCP: index %u, activity timeout", FLOW_IDX(conn));
 			tcp_rst(c, conn);
 		}
 	}