#!/bin/bash
# smb-diag.sh - snapshot Samba + kernel network state so a future failure
# can be diagnosed remotely. Run this on the PXE server BEFORE power-cycling
# when a WinPE re-image client is getting "cannot connect" errors.
#
# Output: /tmp/smb-diag-<timestamp>.log (pastebin-friendly)
#
# Captures: smbd processes, open SMB sessions, port 445 TCP sockets,
#           conntrack, arp, bridge fdb, dnsmasq leases, recent smbd logs.

set -o pipefail

TS=$(date +%Y%m%d-%H%M%S)
OUT=/tmp/smb-diag-$TS.log

exec > >(tee "$OUT") 2>&1

echo "=============================================================="
echo "SMB diagnostic snapshot - $(date)"
echo "=============================================================="

echo
echo "### uptime / kernel ###"
uptime
uname -r

echo
echo "### interfaces + bridge state ###"
ip -brief addr
echo
bridge link show 2>/dev/null
echo
bridge fdb show 2>/dev/null | head -30

echo
echo "### smbd process tree ###"
pstree -p $(systemctl show -p MainPID --value smbd 2>/dev/null) 2>/dev/null
echo
ps -eo pid,ppid,state,command | grep -E 'smbd|nmbd' | grep -v grep

echo
echo "### systemctl status ###"
systemctl is-active smbd nmbd dnsmasq apache2

echo
echo "### smbstatus ###"
smbstatus 2>&1 | head -40

echo
echo "### port 445 sockets ###"
ss -tnp 2>/dev/null | grep :445

echo
echo "### conntrack entries for PXE subnet ###"
if command -v conntrack >/dev/null 2>&1; then
    conntrack -L 2>&1 | grep -E '10\.9\.100' | head -30
    echo "total conntrack entries: $(conntrack -C 2>&1)"
else
    echo "conntrack tool not installed"
fi

echo
echo "### arp / neighbour table for PXE subnet ###"
ip neigh show 2>/dev/null | grep -E '10\.9\.100|br-pxe'

echo
echo "### dnsmasq DHCP leases ###"
cat /var/lib/misc/dnsmasq.leases 2>/dev/null | head -20

echo
echo "### recent smbd log files ###"
ls -la /var/log/samba/ 2>/dev/null | head -20

echo
echo "### recent smbd auth / status errors (all machine logs) ###"
grep -hE 'NT_STATUS|error|denied' /var/log/samba/log.*.log 2>/dev/null | tail -30

echo
echo "### last 20 lines of smbd master log ###"
tail -20 /var/log/samba/log.smbd 2>/dev/null

echo
echo "=============================================================="
echo "Snapshot saved to $OUT"
echo "=============================================================="