From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: jlesev@gmail.com, David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH 5/8] tcp: Return consumed packet count from tcp_data_from_tap()
Date: Fri, 8 Sep 2023 11:49:50 +1000 [thread overview]
Message-ID: <20230908014953.822952-6-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20230908014953.822952-1-david@gibson.dropbear.id.au>
Currently tcp_data_from_tap() is assumed to consume all packets remaining
in the packet pool it is given. However there are some edge cases where
that's not correct. In preparation for fixing those, change it to return
a count of packets consumed and use that in its caller.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
tcp.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/tcp.c b/tcp.c
index 5592998..34c27f0 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2297,8 +2297,10 @@ err:
* @idx: Index of first data packet in pool
*
* #syscalls sendmsg
+ *
+ * Return: count of consumed packets
*/
-static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
+static int tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
const struct pool *p, int idx)
{
int i, iov_i, ack = 0, fin = 0, retr = 0, keep = -1, partial_send = 0;
@@ -2310,7 +2312,7 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
ssize_t n;
if (conn->events == CLOSED)
- return;
+ return p->count - idx;
ASSERT(conn->events & ESTABLISHED);
@@ -2323,19 +2325,19 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
th = packet_get(p, i, 0, sizeof(*th), &len);
if (!th) {
tcp_rst(c, conn);
- return;
+ return p->count - idx;
}
len += sizeof(*th);
off = th->doff * 4UL;
if (off < sizeof(*th) || off > len) {
tcp_rst(c, conn);
- return;
+ return p->count - idx;
}
if (th->rst) {
conn_event(c, conn, CLOSED);
- return;
+ return p->count - idx;
}
len -= off;
@@ -2446,10 +2448,10 @@ eintr:
if (errno == EAGAIN || errno == EWOULDBLOCK) {
tcp_send_flag(c, conn, ACK_IF_NEEDED);
- return;
+ return p->count - idx;
}
tcp_rst(c, conn);
- return;
+ return p->count - idx;
}
if (n < (int)(seq_from_tap - conn->seq_from_tap)) {
@@ -2470,7 +2472,7 @@ out:
conn->seq_dup_ack_approx = conn->seq_from_tap & 0xff;
tcp_send_flag(c, conn, DUP_ACK);
}
- return;
+ return p->count - idx;
}
if (ack && conn->events & TAP_FIN_SENT &&
@@ -2484,6 +2486,8 @@ out:
} else {
tcp_send_flag(c, conn, ACK_IF_NEEDED);
}
+
+ return p->count - idx;
}
/**
@@ -2540,6 +2544,7 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
struct tcphdr *th;
int ack_due = 0;
char *opts;
+ int count;
th = packet_get(p, idx, 0, sizeof(*th), &len);
if (!th)
@@ -2627,7 +2632,7 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
}
/* Established connections accepting data from tap */
- tcp_data_from_tap(c, conn, p, idx);
+ count = tcp_data_from_tap(c, conn, p, idx);
if (conn->seq_ack_to_tap != conn->seq_from_tap)
ack_due = 1;
@@ -2641,7 +2646,7 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
if (ack_due)
conn_flag(c, conn, ACK_TO_TAP_DUE);
- return p->count - idx;
+ return count;
}
/**
--
@@ -2297,8 +2297,10 @@ err:
* @idx: Index of first data packet in pool
*
* #syscalls sendmsg
+ *
+ * Return: count of consumed packets
*/
-static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
+static int tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
const struct pool *p, int idx)
{
int i, iov_i, ack = 0, fin = 0, retr = 0, keep = -1, partial_send = 0;
@@ -2310,7 +2312,7 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
ssize_t n;
if (conn->events == CLOSED)
- return;
+ return p->count - idx;
ASSERT(conn->events & ESTABLISHED);
@@ -2323,19 +2325,19 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
th = packet_get(p, i, 0, sizeof(*th), &len);
if (!th) {
tcp_rst(c, conn);
- return;
+ return p->count - idx;
}
len += sizeof(*th);
off = th->doff * 4UL;
if (off < sizeof(*th) || off > len) {
tcp_rst(c, conn);
- return;
+ return p->count - idx;
}
if (th->rst) {
conn_event(c, conn, CLOSED);
- return;
+ return p->count - idx;
}
len -= off;
@@ -2446,10 +2448,10 @@ eintr:
if (errno == EAGAIN || errno == EWOULDBLOCK) {
tcp_send_flag(c, conn, ACK_IF_NEEDED);
- return;
+ return p->count - idx;
}
tcp_rst(c, conn);
- return;
+ return p->count - idx;
}
if (n < (int)(seq_from_tap - conn->seq_from_tap)) {
@@ -2470,7 +2472,7 @@ out:
conn->seq_dup_ack_approx = conn->seq_from_tap & 0xff;
tcp_send_flag(c, conn, DUP_ACK);
}
- return;
+ return p->count - idx;
}
if (ack && conn->events & TAP_FIN_SENT &&
@@ -2484,6 +2486,8 @@ out:
} else {
tcp_send_flag(c, conn, ACK_IF_NEEDED);
}
+
+ return p->count - idx;
}
/**
@@ -2540,6 +2544,7 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
struct tcphdr *th;
int ack_due = 0;
char *opts;
+ int count;
th = packet_get(p, idx, 0, sizeof(*th), &len);
if (!th)
@@ -2627,7 +2632,7 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
}
/* Established connections accepting data from tap */
- tcp_data_from_tap(c, conn, p, idx);
+ count = tcp_data_from_tap(c, conn, p, idx);
if (conn->seq_ack_to_tap != conn->seq_from_tap)
ack_due = 1;
@@ -2641,7 +2646,7 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
if (ack_due)
conn_flag(c, conn, ACK_TO_TAP_DUE);
- return p->count - idx;
+ return count;
}
/**
--
2.41.0
next prev parent reply other threads:[~2023-09-08 1:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-08 1:49 [PATCH 0/8] Fix a number of bugs with handling of TCP packets from tap David Gibson
2023-09-08 1:49 ` [PATCH 1/8] tcp, tap: Correctly advance through packets in tcp_tap_handler() David Gibson
2023-09-08 1:49 ` [PATCH 2/8] udp, tap: Correctly advance through packets in udp_tap_handler() David Gibson
2023-09-08 1:49 ` [PATCH 3/8] tcp: Remove some redundant packet_get() operations David Gibson
2023-09-08 1:49 ` [PATCH 4/8] tcp: Never hash match closed connections David Gibson
2023-09-08 1:49 ` David Gibson [this message]
2023-09-08 1:49 ` [PATCH 6/8] tcp: Correctly handle RST followed rapidly by SYN David Gibson
2023-09-08 1:49 ` [PATCH 7/8] tcp: Consolidate paths where we initiate reset on tap interface David Gibson
2023-09-08 1:49 ` [PATCH 8/8] tcp: Correct handling of FIN,ACK followed by SYN David Gibson
2023-09-08 15:27 ` [PATCH 0/8] Fix a number of bugs with handling of TCP packets from tap Stefano Brivio
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