On 17 Jan 2025, at 15:25, Adrian Moreno wrote:
> Drop events are generated from the kernel, not ovs-vswitchd so instead
> of relying on nla decoding, copy the skb's device name directly into the
> event.
>
> Signed-off-by: Adrian Moreno <[email protected]>
This patch is giving me odd errors:
1897177.728659707 33 handler206 1058347 ens2f0np0
(system@ovs-system) 0 1496 132 0
1897177.728660453 3 handler172 1058313 ens2f0np0
(system@ovs-system) 0 1496 132 0
1897177.728666183 33 handler206 1058347 ens2f0np0
(system@ovs-system) 0 1496 132 0
Exception ignored on calling ctypes callback function: <function
RingBuf.open_ring_buffer.<locals>.ringbuf_cb_ at 0x7f6e5dc59670>
Traceback (most recent call last):
File "/usr/lib/python3.9/site-packages/bcc/table.py", line 1266, in
ringbuf_cb_
ret = callback(ctx, data, size)
File
"/root/Documents/reviews/OVS_main_DPDK_v24.11.1/ovs_github/utilities/usdt-scripts/./upcall_monitor.py",
line 328, in print_event
port = event.dev_name.decode("utf-8")
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xd8 in position 0: invalid
continuation byte
Exception ignored on calling ctypes callback function: <function
RingBuf.open_ring_buffer.<locals>.ringbuf_cb_ at 0x7f6e5dc59670>
Traceback (most recent call last):
File "/usr/lib/python3.9/site-packages/bcc/table.py", line 1266, in
ringbuf_cb_
ret = callback(ctx, data, size)
I guess the buffer is wrapping, and the entries are not zeroed out, causing
problems in the USDT case. Adding the below solved it for me:
diff --git a/utilities/usdt-scripts/upcall_monitor.py
b/utilities/usdt-scripts/upcall_monitor.py
index 104225cad..3ba17952b 100755
--- a/utilities/usdt-scripts/upcall_monitor.py
+++ b/utilities/usdt-scripts/upcall_monitor.py
@@ -179,6 +179,7 @@ int do_trace(struct pt_regs *ctx) {
event->cpu = bpf_get_smp_processor_id();
event->pid = bpf_get_current_pid_tgid();
event->result = 0;
+ event->dev_name[0] = 0;
bpf_get_current_comm(&event->comm, sizeof(event->comm));
Other than the above, no other comments.
> ---
> utilities/usdt-scripts/upcall_monitor.py | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/utilities/usdt-scripts/upcall_monitor.py
> b/utilities/usdt-scripts/upcall_monitor.py
> index 8943fd205..104225cad 100755
> --- a/utilities/usdt-scripts/upcall_monitor.py
> +++ b/utilities/usdt-scripts/upcall_monitor.py
> @@ -133,6 +133,7 @@ import sys
> # Actual eBPF source code
> #
> ebpf_source = """
> +#include <linux/netdevice.h>
> #include <linux/skbuff.h>
>
> #define MAX_PACKET <MAX_PACKET_VAL>
> @@ -148,6 +149,7 @@ struct event_t {
> u64 key_size;
> char comm[TASK_COMM_LEN];
> char dpif_name[32];
> + char dev_name[16];
> unsigned char pkt[MAX_PACKET];
> unsigned char key[MAX_KEY];
> };
> @@ -237,6 +239,7 @@ int kretprobe__ovs_dp_upcall(struct pt_regs *ctx)
> u64 pid = bpf_get_current_pid_tgid();
> struct inflight_upcall *upcall;
> int ret = PT_REGS_RC(ctx);
> + struct net_device *dev;
> u64 size;
>
> upcall = inflight_upcalls.lookup(&pid);
> @@ -265,6 +268,9 @@ int kretprobe__ovs_dp_upcall(struct pt_regs *ctx)
> event->pkt_size = upcall->skb->len;
> event->upcall_type = upcall->upcall_type;
> event->key_size = 0;
> + bpf_probe_read(&dev, sizeof(upcall->skb->dev),
> + ((char *)upcall->skb + offsetof(struct sk_buff, dev)));
> + bpf_probe_read_kernel(&event->dev_name, 16, dev->name);
>
> size = upcall->skb->len - upcall->skb->data_len;
> if (size > MAX_PACKET) {
> @@ -318,7 +324,9 @@ def print_event(ctx, data, size):
> nla, key_dump = decode_nlm(
> bytes(event.key)[: min(event.key_size, options.flow_key_size)]
> )
> - if "OVS_KEY_ATTR_IN_PORT" in nla:
> + if event.dev_name:
> + port = event.dev_name.decode("utf-8")
> + elif "OVS_KEY_ATTR_IN_PORT" in nla:
> port_no = struct.unpack("=I", nla["OVS_KEY_ATTR_IN_PORT"])[0]
> port = dp_map.get_port_name(dp.partition("@")[-1], port_no)
> else:
> --
> 2.48.1
>
> _______________________________________________
> dev mailing list
> [email protected]
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
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