net/x25/x25_out.c

Source file repositories/reference/linux-study-clean/net/x25/x25_out.c

File Facts

System
Linux kernel
Corpus path
net/x25/x25_out.c
Extension
.c
Size
5243 bytes
Lines
227
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

while (skb->len > 0) {
			release_sock(sk);
			skbn = sock_alloc_send_skb(sk, frontlen + max_len,
						   noblock, &err);
			lock_sock(sk);
			if (!skbn) {
				if (err == -EWOULDBLOCK && noblock){
					kfree_skb(skb);
					return sent;
				}
				net_dbg_ratelimited("x25_output: fragment alloc"
					       " failed, err=%d, %d bytes "
					       "sent\n", err, sent);
				return err;
			}

			skb_reserve(skbn, frontlen);

			len = max_len > skb->len ? skb->len : max_len;

			/* Copy the user data */
			skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
			skb_pull(skb, len);

			/* Duplicate the Header */
			skb_push(skbn, header_len);
			skb_copy_to_linear_data(skbn, header, header_len);

			if (skb->len > 0) {
				if (x25->neighbour->extended)
					skbn->data[3] |= X25_EXT_M_BIT;
				else
					skbn->data[2] |= X25_STD_M_BIT;
			}

			skb_queue_tail(&sk->sk_write_queue, skbn);
			sent += len;
		}

		kfree_skb(skb);
	} else {
		skb_queue_tail(&sk->sk_write_queue, skb);
		sent = skb->len - header_len;
	}
	return sent;
}

/*
 *	This procedure is passed a buffer descriptor for an iframe. It builds
 *	the rest of the control part of the frame and then writes it out.
 */
static void x25_send_iframe(struct sock *sk, struct sk_buff *skb)
{
	struct x25_sock *x25 = x25_sk(sk);

	if (!skb)
		return;

	if (x25->neighbour->extended) {
		skb->data[2]  = (x25->vs << 1) & 0xFE;
		skb->data[3] &= X25_EXT_M_BIT;
		skb->data[3] |= (x25->vr << 1) & 0xFE;
	} else {
		skb->data[2] &= X25_STD_M_BIT;
		skb->data[2] |= (x25->vs << 1) & 0x0E;
		skb->data[2] |= (x25->vr << 5) & 0xE0;
	}

	x25_transmit_link(skb, x25->neighbour);
}

void x25_kick(struct sock *sk)
{
	struct sk_buff *skb, *skbn;
	unsigned short start, end;
	int modulus;
	struct x25_sock *x25 = x25_sk(sk);

	if (x25->state != X25_STATE_3)
		return;

	/*
	 *	Transmit interrupt data.
	 */
	if (skb_peek(&x25->interrupt_out_queue) != NULL &&
		!test_and_set_bit(X25_INTERRUPT_FLAG, &x25->flags)) {

		skb = skb_dequeue(&x25->interrupt_out_queue);
		x25_transmit_link(skb, x25->neighbour);
	}

Annotation

Implementation Notes