BGP 协议基础

# /etc/calico/confd/config/bird.cfg (由 confd 生成)

# Router ID
router id 192.168.1.100;

# 日志配置
log syslog all;

# 内核协议 - 同步路由到内核
protocol kernel {
    learn;             # 学习内核路由
    persist;           # 退出时保留路由
    scan time 2;       # 扫描间隔
    import all;
    export filter {
        if net ~ 10.244.0.0/16 then accept;
        reject;
    };
    graceful restart;
}

# 设备协议
protocol device {
    scan time 2;
}

# 直连路由
protocol direct {
    interface "eth*", "en*";
}

# BGP 模板
template bgp bgp_template {
    local as 64512;
    multihop;
    import all;
    export filter {
        if net ~ 10.244.0.0/16 then accept;
        reject;
    };
    graceful restart;
}

# BGP Peer
protocol bgp peer_192_168_1_101 from bgp_template {
    neighbor 192.168.1.101 as 64512;
}

protocol bgp peer_192_168_1_102 from bgp_template {
    neighbor 192.168.1.102 as 64512;
}

# 进入 BIRD 命令行（在 calico-node 容器中）
kubectl exec -it <calico-node-pod> -c calico-node -- birdcl

# 常用命令
bird> show protocols              # 显示所有协议状态
bird> show protocols all bgp1     # 显示特定协议详情
bird> show route                  # 显示路由表
bird> show route for 10.244.1.0/24  # 查询特定路由
bird> show route protocol bgp1    # 显示从 bgp1 学到的路由
bird> show route export bgp1      # 显示导出给 bgp1 的路由
bird> configure                   # 重新加载配置
bird> restart bgp1                # 重启特定协议

# 安装 BIRD
sudo apt-get install bird2

# 创建 namespace
sudo ip netns add r1
sudo ip netns add r2

# 创建 veth pair 连接两个 namespace
sudo ip link add veth-r1 type veth peer name veth-r2
sudo ip link set veth-r1 netns r1
sudo ip link set veth-r2 netns r2

# 配置 IP
sudo ip netns exec r1 ip addr add 192.168.1.1/24 dev veth-r1
sudo ip netns exec r1 ip link set veth-r1 up
sudo ip netns exec r1 ip link set lo up

sudo ip netns exec r2 ip addr add 192.168.1.2/24 dev veth-r2
sudo ip netns exec r2 ip link set veth-r2 up
sudo ip netns exec r2 ip link set lo up

# 添加模拟网络
sudo ip netns exec r1 ip addr add 10.1.0.1/24 dev lo
sudo ip netns exec r2 ip addr add 10.2.0.1/24 dev lo

# 测试连通性
sudo ip netns exec r1 ping -c 2 192.168.1.2

cat > /tmp/bird-r1.conf << 'EOF'
log stderr all;
router id 1.1.1.1;

protocol device {
    scan time 2;
}

protocol direct {
    ipv4;
    interface "lo";
}

protocol kernel {
    ipv4 {
        import all;
        export all;
    };
}

protocol bgp peer_r2 {
    local 192.168.1.1 as 64512;
    neighbor 192.168.1.2 as 64513;
    ipv4 {
        import all;
        export where net ~ 10.1.0.0/24;
    };
}
EOF

cat > /tmp/bird-r2.conf << 'EOF'
log stderr all;
router id 2.2.2.2;

protocol device {
    scan time 2;
}

protocol direct {
    ipv4;
    interface "lo";
}

protocol kernel {
    ipv4 {
        import all;
        export all;
    };
}

protocol bgp peer_r1 {
    local 192.168.1.2 as 64513;
    neighbor 192.168.1.1 as 64512;
    ipv4 {
        import all;
        export where net ~ 10.2.0.0/24;
    };
}
EOF

# 在 r1 中启动 BIRD
sudo ip netns exec r1 bird -c /tmp/bird-r1.conf -s /tmp/bird-r1.ctl -P /tmp/bird-r1.pid

# 在 r2 中启动 BIRD
sudo ip netns exec r2 bird -c /tmp/bird-r2.conf -s /tmp/bird-r2.ctl -P /tmp/bird-r2.pid

# 等待几秒让 BGP 建立
sleep 5

# 查看 R1 的 BGP 状态
sudo ip netns exec r1 birdc -s /tmp/bird-r1.ctl show protocols
# 输出应显示 peer_r2 为 Established

# 查看学到的路由
sudo ip netns exec r1 birdc -s /tmp/bird-r1.ctl show route
# 应该看到 10.2.0.0/24 via 192.168.1.2

# 查看内核路由表
sudo ip netns exec r1 ip route
# 10.2.0.0/24 via 192.168.1.2 dev veth-r1 proto bird

# 测试跨 AS 通信
sudo ip netns exec r1 ping -c 2 10.2.0.1

# 查看详细的协议信息
sudo ip netns exec r1 birdc -s /tmp/bird-r1.ctl show protocols all peer_r2

# 输出示例：
# peer_r2    BGP        ---        up     2024-01-15    Established
#   BGP state:          Established
#     Neighbor address: 192.168.1.2
#     Neighbor AS:      64513
#     Local AS:         64512
#     Neighbor ID:      2.2.2.2
#     ...
#   Channel ipv4
#     State:          UP
#     Routes:         1 imported, 1 exported

# 停止 BIRD
sudo kill $(cat /tmp/bird-r1.pid)
sudo kill $(cat /tmp/bird-r2.pid)

# 删除 namespace
sudo ip netns del r1
sudo ip netns del r2

# 清理文件
rm -f /tmp/bird-r*.conf /tmp/bird-r*.ctl /tmp/bird-r*.pid

# 查看 Calico 节点的 BGP 状态
kubectl exec -it -n kube-system <calico-node-pod> -c calico-node -- birdcl show protocols

# 查看路由
kubectl exec -it -n kube-system <calico-node-pod> -c calico-node -- birdcl show route

# 使用 calicoctl
calicoctl node status

# 输出示例：
# Calico process is running.
#
# IPv4 BGP status
# +--------------+-------------------+-------+----------+-------------+
# | PEER ADDRESS |     PEER TYPE     | STATE |  SINCE   |    INFO     |
# +--------------+-------------------+-------+----------+-------------+
# | 192.168.1.2  | node-to-node mesh | up    | 10:23:45 | Established |
# | 192.168.1.3  | node-to-node mesh | up    | 10:23:46 | Established |
# +--------------+-------------------+-------+----------+-------------+