esp_ping session does not stop when count is greater than 65535 (IDFGH-17693)

[brabema]

Checklist

• Checked the issue tracker for similar issues to ensure this is not a duplicate
• Read the documentation to confirm the issue is not addressed there and your configuration is set correctly
• Tested with the latest version to ensure the issue hasn't been fixed

How often does this bug occurs?

always

Expected behavior

A finite ping session should stop after the configured number of ping procedures.

Since esp_ping_config_t::count is a uint32_t and 0 is documented separately as infinite mode, any non-zero count value should be treated as a finite count.

For example, if config.count = 65536, the session should send 65536 ping requests and then call the on_ping_end callback.

If values greater than UINT16_MAX are not intended to be supported, esp_ping_new_session() should reject such configurations with ESP_ERR_INVALID_ARG instead of accepting them and running indefinitely.

Actual behavior (suspected bug)

For config.count >= 65536, the ping session does not appear to stop after the configured number of ping procedures.

The implementation uses the 16-bit ICMP sequence number in the loop condition:

(ep->count == 0) || (ep->packet_hdr->seqno < ep->count)

Steps to reproduce the behavior

1. Download and extract the attached reproducer project:
   [ping_seqno_wrap_repro_poc.zip](https://github.com/user-attachments/
   files/28095594/ping_seqno_wrap_repro_poc.zip)

2. Build the attached ESP-IDF project for an ESP32 target.

3. Flash the built application to an ESP32 device and open the serial monitor.

4. Wait until the reproducer reaches the 16-bit ICMP sequence number wrap. On the
   tested ESP32 setup.

5. Confirm that the serial monitor prints the wrap condition and reproduction
   markers:

   seqno wrapped: previous=65535 current=0 transmitted=65536
   REPRODUCED: seqno wrapped while count=65536 was still not reached
   this demonstrates the u16 seqno vs uint32 count loop-condition bug
   
   

The reproducer starts an esp_ping session against 127.0.0.1 with count=65536,
interval_ms=0, and timeout_ms=1. WiFi or external network access is not required,
because the target is the lwIP loopback address. The reproducer stops the ping
session only after observing that the 16-bit sequence number wrapped while the
configured 32-bit count had not been naturally completed.

Project release version

lwIP 2.2.0-esp, ESP-IDF v6.0.1

System architecture

Intel/AMD 64-bit (modern PC, older Mac)

Operating system

Linux

Operating system version

openSUSE Leap 15.6, Linux kernel 6.4.0-150600.23.103-default.

Shell

ZSH

Additional context

The reproducer starts an esp_ping session against 127.0.0.1 with count=65536,
interval_ms=0, and timeout_ms=1. WiFi or external network access is not required,
because the target is the lwIP loopback address. The reproducer stops the ping
session only after observing that the 16-bit sequence number wrapped while the
configured 32-bit count had not been naturally completed.