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, skb->dev, ETH_P_802_2, da, sa, 34 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 unsigned char *dmac, unsigned char dsap) 60 { 61 int rc; 62 llc_pdu_header_init(skb, LLC_PDU_TYPE_U, sap->laddr.lsap, 63 dsap, LLC_PDU_CMD); 64 llc_pdu_init_as_ui_cmd(skb); 65 rc = llc_mac_hdr_init(skb, skb->dev->dev_addr, 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