Linux pppoe代码

以下是Linux中PPPoE的相关代码：

1. PPPoE协议处理

struct pppox_sock {
    __u16               protocol;
    __u16               flags;
    unsigned long       state;
    struct socket       *sk;
    pid_t               pid;
    struct sk_buff_head rx_queue;
    struct sk_buff_head tx_queue;
    struct sk_buff_head def_queue;
    struct net_device   *dev;
    struct hlist_node   node;
    struct mutex        mutex;
    wait_queue_head_t   waitq;
};

2. PPPoE拨号连接过程

pppoe_connect(struct sock *sk, struct sockaddr_pppoe *addr)
{
    struct pppox_sock *po;
    struct net_device *dev;
    struct sock *sk2;
    int err;
 
    po = pppox_sk(sk);
    if (po->dev) {
        pppoe_err(po->sk, "already connected");
        return -EISCONN;
    }
 
    dev = dev_get_by_name(addr->iface);
    if (!dev) {
        pppoe_err(po->sk, "no such device: %s", addr->iface);
        return -ENODEV;
    }
 
    if (dev->flags & IFF_NOARP) {
        pppoe_err(po->sk, "device %s is not ARPable", addr->iface);
        dev_put(dev);
        return -EINVAL;
    }
 
    sk2 = pppox_lookup(dev_net(dev), ETH_P_PPP_SES, NULL, 0);
    if (!sk2) {
        pppoe_err(po->sk, "no PPPoE session socket available");
        dev_put(dev);
        return -ECONNREFUSED;
    }
 
    po->dev = dev;
    po->protocol = ETH_P_PPP_SES;
    po->pid = current->pid;
 
    err = pppoe_send_padi(po);
    if (err) {
        pppoe_err(po->sk, "error sending PADI, err=%d", err);
        po->dev = NULL;
        po->protocol = 0;
        po->pid = 0;
        dev_put(dev);
        sock_put(sk2);
        return err;
    }
 
    pppoe_info(po->sk, "sent PADI on %s", addr->iface);
 
    po->state = PPPOX_CONNECTED;
    skb_queue_head_init(&po->tx_queue);
    skb_queue_head_init(&po->rx_queue);
    skb_queue_head_init(&po->def_queue);
    mutex_init(&po->mutex);
    init_waitqueue_head(&po->waitq);
 
    po->sk = sk2;
    po->flags |= PPPOX_ROUTE;
 
    dev_put(dev);
    return 0;
}

3. PPPoE断开连接过程

pppoe_disconnect(struct sock *sk)
{
    struct pppox_sock *po;
    struct net_device *dev;
    struct sock *sk2;
 
    po = pppox_sk(sk);
    if (!po->dev) {
        pppoe_err(po->sk, "not connected");
        return -ENOTCONN;
    }
 
    dev = po->dev;
    sk2 = po->sk;
 
    if (po->flags & PPPOX_ROUTE)
        pppoe_remove_route(po);
 
    po->dev = NULL;
    po->protocol = 0;
    po->pid = 0;
    po->state = PPPOX_DISCONNECTED;
 
    sock_put(sk2);
    dev_put(dev);
 
    skb_queue_purge(&po->tx_queue);
    skb_queue_purge(&po->rx_queue);
    skb_queue_purge(&po->def_queue);
 
    return 0;
}

以上是Linux中PPPoE的相关代码，可以帮助理解PPPoE协议的实现过程。