net/x25/af_x25.c

Source file repositories/reference/linux-study-clean/net/x25/af_x25.c

File Facts

System
Linux kernel
Corpus path
net/x25/af_x25.c
Extension
.c
Size
41332 bytes
Lines
1852
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: operation-table or driver-model contract
Status
pattern 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

static const struct proto_ops x25_proto_ops;

static const struct x25_address null_x25_address = {"               "};

#ifdef CONFIG_COMPAT
struct compat_x25_subscrip_struct {
	char device[200-sizeof(compat_ulong_t)];
	compat_ulong_t global_facil_mask;
	compat_uint_t extended;
};
#endif


int x25_parse_address_block(struct sk_buff *skb,
		struct x25_address *called_addr,
		struct x25_address *calling_addr)
{
	unsigned char len;
	int needed;
	int rc;

	if (!pskb_may_pull(skb, 1)) {
		/* packet has no address block */
		rc = 0;
		goto empty;
	}

	len = *skb->data;
	needed = 1 + ((len >> 4) + (len & 0x0f) + 1) / 2;

	if (!pskb_may_pull(skb, needed)) {
		/* packet is too short to hold the addresses it claims
		   to hold */
		rc = -1;
		goto empty;
	}

	return x25_addr_ntoa(skb->data, called_addr, calling_addr);

empty:
	*called_addr->x25_addr = 0;
	*calling_addr->x25_addr = 0;

	return rc;
}


int x25_addr_ntoa(unsigned char *p, struct x25_address *called_addr,
		  struct x25_address *calling_addr)
{
	unsigned int called_len, calling_len;
	char *called, *calling;
	unsigned int i;

	called_len  = (*p >> 0) & 0x0F;
	calling_len = (*p >> 4) & 0x0F;

	called  = called_addr->x25_addr;
	calling = calling_addr->x25_addr;
	p++;

	for (i = 0; i < (called_len + calling_len); i++) {
		if (i < called_len) {
			if (i % 2 != 0) {
				*called++ = ((*p >> 0) & 0x0F) + '0';
				p++;
			} else {
				*called++ = ((*p >> 4) & 0x0F) + '0';
			}
		} else {
			if (i % 2 != 0) {
				*calling++ = ((*p >> 0) & 0x0F) + '0';
				p++;
			} else {
				*calling++ = ((*p >> 4) & 0x0F) + '0';
			}
		}
	}

	*called = *calling = '\0';

	return 1 + (called_len + calling_len + 1) / 2;
}

int x25_addr_aton(unsigned char *p, struct x25_address *called_addr,
		  struct x25_address *calling_addr)
{
	unsigned int called_len, calling_len;
	char *called, *calling;
	int i;

Annotation

Implementation Notes