cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cfdgml.c (2846B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (C) ST-Ericsson AB 2010
      4 * Author:	Sjur Brendeland
      5 */
      6
      7#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
      8
      9#include <linux/stddef.h>
     10#include <linux/spinlock.h>
     11#include <linux/slab.h>
     12#include <net/caif/caif_layer.h>
     13#include <net/caif/cfsrvl.h>
     14#include <net/caif/cfpkt.h>
     15
     16
     17#define container_obj(layr) ((struct cfsrvl *) layr)
     18
     19#define DGM_CMD_BIT  0x80
     20#define DGM_FLOW_OFF 0x81
     21#define DGM_FLOW_ON  0x80
     22#define DGM_MTU 1500
     23
     24static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
     25static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
     26
     27struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info)
     28{
     29	struct cfsrvl *dgm = kzalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
     30	if (!dgm)
     31		return NULL;
     32	caif_assert(offsetof(struct cfsrvl, layer) == 0);
     33	cfsrvl_init(dgm, channel_id, dev_info, true);
     34	dgm->layer.receive = cfdgml_receive;
     35	dgm->layer.transmit = cfdgml_transmit;
     36	snprintf(dgm->layer.name, CAIF_LAYER_NAME_SZ, "dgm%d", channel_id);
     37	return &dgm->layer;
     38}
     39
     40static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
     41{
     42	u8 cmd = -1;
     43	u8 dgmhdr[3];
     44	int ret;
     45	caif_assert(layr->up != NULL);
     46	caif_assert(layr->receive != NULL);
     47	caif_assert(layr->ctrlcmd != NULL);
     48
     49	if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
     50		pr_err("Packet is erroneous!\n");
     51		cfpkt_destroy(pkt);
     52		return -EPROTO;
     53	}
     54
     55	if ((cmd & DGM_CMD_BIT) == 0) {
     56		if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
     57			pr_err("Packet is erroneous!\n");
     58			cfpkt_destroy(pkt);
     59			return -EPROTO;
     60		}
     61		ret = layr->up->receive(layr->up, pkt);
     62		return ret;
     63	}
     64
     65	switch (cmd) {
     66	case DGM_FLOW_OFF:	/* FLOW OFF */
     67		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
     68		cfpkt_destroy(pkt);
     69		return 0;
     70	case DGM_FLOW_ON:	/* FLOW ON */
     71		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
     72		cfpkt_destroy(pkt);
     73		return 0;
     74	default:
     75		cfpkt_destroy(pkt);
     76		pr_info("Unknown datagram control %d (0x%x)\n", cmd, cmd);
     77		return -EPROTO;
     78	}
     79}
     80
     81static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
     82{
     83	u8 packet_type;
     84	u32 zero = 0;
     85	struct caif_payload_info *info;
     86	struct cfsrvl *service = container_obj(layr);
     87	int ret;
     88
     89	if (!cfsrvl_ready(service, &ret)) {
     90		cfpkt_destroy(pkt);
     91		return ret;
     92	}
     93
     94	/* STE Modem cannot handle more than 1500 bytes datagrams */
     95	if (cfpkt_getlen(pkt) > DGM_MTU) {
     96		cfpkt_destroy(pkt);
     97		return -EMSGSIZE;
     98	}
     99
    100	cfpkt_add_head(pkt, &zero, 3);
    101	packet_type = 0x08; /* B9 set - UNCLASSIFIED */
    102	cfpkt_add_head(pkt, &packet_type, 1);
    103
    104	/* Add info for MUX-layer to route the packet out. */
    105	info = cfpkt_info(pkt);
    106	info->channel_id = service->layer.id;
    107	/* To optimize alignment, we add up the size of CAIF header
    108	 * before payload.
    109	 */
    110	info->hdr_len = 4;
    111	info->dev_info = &service->dev_info;
    112	return layr->dn->transmit(layr->dn, pkt);
    113}