#!/bin/bash
# 查 api.cloudflare.com 到底该用哪个 IP。
#
# 现在钉的 104.16.132.229 返回的是 Cloudflare 错误页（error 1034），
# 说明这个 IP 不对 —— 我当初是随便挑的一个 Cloudflare 网段地址。
set -u

echo "===== 1. 当前响应内容到底是什么 ====="
curl -4 -s -D /tmp/h.txt -o /tmp/b.txt https://api.cloudflare.com/client/v4/user 2>/dev/null
echo "  响应头前几行:"
head -8 /tmp/h.txt | sed 's/^/    /'
echo
echo "  响应体前 300 字节:"
head -c 300 /tmp/b.txt | sed 's/^/    /'
echo
echo

echo "===== 2. 用公共 DNS 查真实 IP（绕开本地解析）====="
for dns in 1.1.1.1 8.8.8.8 223.5.5.5; do
    echo "  --- 经 $dns ---"
    timeout 8 getent ahostsv4 api.cloudflare.com >/dev/null 2>&1
    # 用 python 发 DNS 查询（设备上不一定有 dig/nslookup）
    python3 - "$dns" <<'PY' 2>/dev/null || echo "      （查不了）"
import socket, struct, sys

dns = sys.argv[1]
name = "api.cloudflare.com"
# 手搓一个 DNS A 查询
tid = 0x1234
flags = 0x0100
q = struct.pack(">HHHHHH", tid, flags, 1, 0, 0, 0)
for part in name.split("."):
    q += bytes([len(part)]) + part.encode()
q += b"\x00" + struct.pack(">HH", 1, 1)

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.settimeout(5)
try:
    s.sendto(q, (dns, 53))
    data, _ = s.recvfrom(2048)
except Exception as exc:
    print(f"      查询失败: {exc}")
    raise SystemExit

# 跳过 header + question
idx = 12
while data[idx] != 0:
    idx += data[idx] + 1
idx += 5
ancount = struct.unpack(">H", data[6:8])[0]
found = []
for _ in range(ancount):
    if data[idx] & 0xC0:
        idx += 2
    else:
        while data[idx] != 0:
            idx += data[idx] + 1
        idx += 1
    rtype, _cls, _ttl, rdlen = struct.unpack(">HHIH", data[idx:idx+10])
    idx += 10
    if rtype == 1 and rdlen == 4:
        found.append(".".join(str(b) for b in data[idx:idx+4]))
    idx += rdlen
print("      " + (", ".join(found) if found else "没有 A 记录"))
PY
done
echo

echo "===== 3. 挨个试候选 IP，看哪个返回正常的 API JSON ====="
for ip in 104.16.132.229 104.16.133.229 104.17.0.1 104.18.0.1 172.64.0.1 162.159.0.1; do
    OUT=$(timeout 12 curl -4 -s -w '\n%{http_code}' \
          --resolve "api.cloudflare.com:443:$ip" \
          https://api.cloudflare.com/client/v4/user 2>/dev/null)
    CODE=$(echo "$OUT" | tail -1)
    FIRST=$(echo "$OUT" | head -c 90 | tr -d '\n')
    printf "  %-16s HTTP %-4s  %s\n" "$ip" "${CODE:-超时}" "$FIRST"
done
echo

echo "===== 4. 去掉 hosts 钉的 IP，用系统解析试试 ====="
# 临时备份并移除
cp /etc/hosts /tmp/hosts.bak
grep -v 'api.cloudflare.com' /etc/hosts > /tmp/hosts.new
cat /tmp/hosts.new > /etc/hosts
echo "  现在的解析: $(getent ahostsv4 api.cloudflare.com | head -1 | awk '{print $1}')"
OUT=$(timeout 12 curl -4 -s -w '\n%{http_code}' https://api.cloudflare.com/client/v4/user 2>/dev/null)
echo "  HTTP $(echo "$OUT" | tail -1)   $(echo "$OUT" | head -c 90)"
echo
echo "  把 hosts 恢复回去（钉 IP 还是需要的，不然全乱）"
cp /tmp/hosts.bak /etc/hosts
getent ahostsv4 api.cloudflare.com | head -1 | sed 's/^/    /'