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Release 4.15 net/llc/llc_input.c

Directory: net/llc
/*
 * llc_input.c - Minimal input path for LLC
 *
 * Copyright (c) 1997 by Procom Technology, Inc.
 *               2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 * This program can be redistributed or modified under the terms of the
 * GNU General Public License as published by the Free Software Foundation.
 * This program is distributed without any warranty or implied warranty
 * of merchantability or fitness for a particular purpose.
 *
 * See the GNU General Public License for more details.
 */
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/llc.h>
#include <net/llc_pdu.h>
#include <net/llc_sap.h>

#if 0
#define dprintk(args...) printk(KERN_DEBUG args)
#else

#define dprintk(args...)
#endif

/*
 * Packet handler for the station, registerable because in the minimal
 * LLC core that is taking shape only the very minimal subset of LLC that
 * is needed for things like IPX, Appletalk, etc will stay, with all the
 * rest in the llc1 and llc2 modules.
 */

static void (*llc_station_handler)(struct sk_buff *skb);

/*
 * Packet handlers for LLC_DEST_SAP and LLC_DEST_CONN.
 */

static void (*llc_type_handlers[2])(struct llc_sap *sap,
				    struct sk_buff *skb);


void llc_add_pack(int type, void (*handler)(struct llc_sap *sap, struct sk_buff *skb)) { smp_wmb(); /* ensure initialisation is complete before it's called */ if (type == LLC_DEST_SAP || type == LLC_DEST_CONN) llc_type_handlers[type - 1] = handler; }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo4491.67%375.00%
Ben Hutchings48.33%125.00%
Total48100.00%4100.00%


void llc_remove_pack(int type) { if (type == LLC_DEST_SAP || type == LLC_DEST_CONN) llc_type_handlers[type - 1] = NULL; synchronize_net(); }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo2790.00%375.00%
Ben Hutchings310.00%125.00%
Total30100.00%4100.00%


void llc_set_station_handler(void (*handler)(struct sk_buff *skb)) { /* Ensure initialisation is complete before it's called */ if (handler) smp_wmb(); llc_station_handler = handler; if (!handler) synchronize_net(); }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo2156.76%150.00%
Ben Hutchings1643.24%150.00%
Total37100.00%2100.00%

/** * llc_pdu_type - returns which LLC component must handle for PDU * @skb: input skb * * This function returns which LLC component must handle this PDU. */
static __inline__ int llc_pdu_type(struct sk_buff *skb) { int type = LLC_DEST_CONN; /* I-PDU or S-PDU type */ struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) != LLC_PDU_TYPE_U) goto out; switch (LLC_U_PDU_CMD(pdu)) { case LLC_1_PDU_CMD_XID: case LLC_1_PDU_CMD_UI: case LLC_1_PDU_CMD_TEST: type = LLC_DEST_SAP; break; case LLC_2_PDU_CMD_SABME: case LLC_2_PDU_CMD_DISC: case LLC_2_PDU_RSP_UA: case LLC_2_PDU_RSP_DM: case LLC_2_PDU_RSP_FRMR: break; default: type = LLC_DEST_INVALID; break; } out: return type; }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo93100.00%1100.00%
Total93100.00%1100.00%

/** * llc_fixup_skb - initializes skb pointers * @skb: This argument points to incoming skb * * Initializes internal skb pointer to start of network layer by deriving * length of LLC header; finds length of LLC control field in LLC header * by looking at the two lowest-order bits of the first control field * byte; field is either 3 or 4 bytes long. */
static inline int llc_fixup_skb(struct sk_buff *skb) { u8 llc_len = 2; struct llc_pdu_un *pdu; if (unlikely(!pskb_may_pull(skb, sizeof(*pdu)))) return 0; pdu = (struct llc_pdu_un *)skb->data; if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) == LLC_PDU_TYPE_U) llc_len = 1; llc_len += 2; if (unlikely(!pskb_may_pull(skb, llc_len))) return 0; skb->transport_header += llc_len; skb_pull(skb, llc_len); if (skb->protocol == htons(ETH_P_802_2)) { __be16 pdulen = eth_hdr(skb)->h_proto; s32 data_size = ntohs(pdulen) - llc_len; if (data_size < 0 || !pskb_may_pull(skb, data_size)) return 0; if (unlikely(pskb_trim_rcsum(skb, data_size))) return 0; } return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo12271.76%444.44%
Jochen Friedrich1810.59%111.11%
David S. Miller148.24%222.22%
Joonwoo Park148.24%111.11%
Al Viro21.18%111.11%
Total170100.00%9100.00%

/** * llc_rcv - 802.2 entry point from net lower layers * @skb: received pdu * @dev: device that receive pdu * @pt: packet type * * When the system receives a 802.2 frame this function is called. It * checks SAP and connection of received pdu and passes frame to * llc_{station,sap,conn}_rcv for sending to proper state machine. If * the frame is related to a busy connection (a connection is sending * data now), it queues this frame in the connection's backlog. */
int llc_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) { struct llc_sap *sap; struct llc_pdu_sn *pdu; int dest; int (*rcv)(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *); void (*sta_handler)(struct sk_buff *skb); void (*sap_handler)(struct llc_sap *sap, struct sk_buff *skb); if (!net_eq(dev_net(dev), &init_net)) goto drop; /* * When the interface is in promisc. mode, drop all the crap that it * receives, do not try to analyse it. */ if (unlikely(skb->pkt_type == PACKET_OTHERHOST)) { dprintk("%s: PACKET_OTHERHOST\n", __func__); goto drop; } skb = skb_share_check(skb, GFP_ATOMIC); if (unlikely(!skb)) goto out; if (unlikely(!llc_fixup_skb(skb))) goto drop; pdu = llc_pdu_sn_hdr(skb); if (unlikely(!pdu->dsap)) /* NULL DSAP, refer to station */ goto handle_station; sap = llc_sap_find(pdu->dsap); if (unlikely(!sap)) {/* unknown SAP */ dprintk("%s: llc_sap_find(%02X) failed!\n", __func__, pdu->dsap); goto drop; } /* * First the upper layer protocols that don't need the full * LLC functionality */ rcv = rcu_dereference(sap->rcv_func); dest = llc_pdu_type(skb); sap_handler = dest ? READ_ONCE(llc_type_handlers[dest - 1]) : NULL; if (unlikely(!sap_handler)) { if (rcv) rcv(skb, dev, pt, orig_dev); else kfree_skb(skb); } else { if (rcv) { struct sk_buff *cskb = skb_clone(skb, GFP_ATOMIC); if (cskb) rcv(cskb, dev, pt, orig_dev); } sap_handler(sap, skb); } llc_sap_put(sap); out: return 0; drop: kfree_skb(skb); goto out; handle_station: sta_handler = READ_ONCE(llc_station_handler); if (!sta_handler) goto drop; sta_handler(skb); goto out; }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo18349.19%1557.69%
Stephen Hemminger6617.74%311.54%
Ben Hutchings5514.78%13.85%
Changli Gao4211.29%13.85%
Eric W. Biedermann92.42%13.85%
Hideaki Yoshifuji / 吉藤英明82.15%27.69%
David S. Miller51.34%13.85%
Harvey Harrison20.54%13.85%
Mark Rutland20.54%13.85%
Total372100.00%26100.00%

EXPORT_SYMBOL(llc_add_pack); EXPORT_SYMBOL(llc_remove_pack); EXPORT_SYMBOL(llc_set_station_handler);

Overall Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo57968.28%2255.00%
Ben Hutchings789.20%12.50%
Stephen Hemminger667.78%37.50%
Changli Gao424.95%12.50%
David S. Miller192.24%37.50%
Jochen Friedrich182.12%12.50%
Joonwoo Park141.65%12.50%
Eric W. Biedermann121.42%12.50%
Hideaki Yoshifuji / 吉藤英明80.94%25.00%
Paul Gortmaker30.35%12.50%
Tejun Heo30.35%12.50%
Al Viro20.24%12.50%
Mark Rutland20.24%12.50%
Harvey Harrison20.24%12.50%
Total848100.00%40100.00%
Directory: net/llc
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