1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * llc_output.c - LLC minimal output path |
4 | * |
5 | * Copyright (c) 1997 by Procom Technology, Inc. |
6 | * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br> |
7 | */ |
8 | |
9 | #include <linux/if_arp.h> |
10 | #include <linux/netdevice.h> |
11 | #include <linux/skbuff.h> |
12 | #include <linux/export.h> |
13 | #include <net/llc.h> |
14 | #include <net/llc_pdu.h> |
15 | |
16 | /** |
17 | * llc_mac_hdr_init - fills MAC header fields |
18 | * @skb: Address of the frame to initialize its MAC header |
19 | * @sa: The MAC source address |
20 | * @da: The MAC destination address |
21 | * |
22 | * Fills MAC header fields, depending on MAC type. Returns 0, If MAC type |
23 | * is a valid type and initialization completes correctly 1, otherwise. |
24 | */ |
25 | int llc_mac_hdr_init(struct sk_buff *skb, |
26 | const unsigned char *sa, const unsigned char *da) |
27 | { |
28 | int rc = -EINVAL; |
29 | |
30 | switch (skb->dev->type) { |
31 | case ARPHRD_ETHER: |
32 | case ARPHRD_LOOPBACK: |
33 | rc = dev_hard_header(skb, dev: skb->dev, ETH_P_802_2, daddr: da, saddr: sa, |
34 | len: skb->len); |
35 | if (rc > 0) |
36 | rc = 0; |
37 | break; |
38 | default: |
39 | break; |
40 | } |
41 | return rc; |
42 | } |
43 | |
44 | /** |
45 | * llc_build_and_send_ui_pkt - unitdata request interface for upper layers |
46 | * @sap: sap to use |
47 | * @skb: packet to send |
48 | * @dmac: destination mac address |
49 | * @dsap: destination sap |
50 | * |
51 | * Upper layers calls this function when upper layer wants to send data |
52 | * using connection-less mode communication (UI pdu). |
53 | * |
54 | * Accept data frame from network layer to be sent using connection- |
55 | * less mode communication; timeout/retries handled by network layer; |
56 | * package primitive as an event and send to SAP event handler |
57 | */ |
58 | int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb, |
59 | const unsigned char *dmac, unsigned char dsap) |
60 | { |
61 | int rc; |
62 | llc_pdu_header_init(skb, LLC_PDU_TYPE_U, ssap: sap->laddr.lsap, |
63 | dsap, LLC_PDU_CMD); |
64 | llc_pdu_init_as_ui_cmd(skb); |
65 | rc = llc_mac_hdr_init(skb, sa: skb->dev->dev_addr, da: dmac); |
66 | if (likely(!rc)) |
67 | rc = dev_queue_xmit(skb); |
68 | else |
69 | kfree_skb(skb); |
70 | return rc; |
71 | } |
72 | |
73 | EXPORT_SYMBOL(llc_mac_hdr_init); |
74 | EXPORT_SYMBOL(llc_build_and_send_ui_pkt); |
75 | |