diff options
Diffstat (limited to 'net/can/gw.c')
| -rw-r--r-- | net/can/gw.c | 998 |
1 files changed, 998 insertions, 0 deletions
diff --git a/net/can/gw.c b/net/can/gw.c new file mode 100644 index 000000000..a6f448e18 --- /dev/null +++ b/net/can/gw.c @@ -0,0 +1,998 @@ +/* + * gw.c - CAN frame Gateway/Router/Bridge with netlink interface + * + * Copyright (c) 2011 Volkswagen Group Electronic Research + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Volkswagen nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * Alternatively, provided that this notice is retained in full, this + * software may be distributed under the terms of the GNU General + * Public License ("GPL") version 2, in which case the provisions of the + * GPL apply INSTEAD OF those given above. + * + * The provided data structures and external interfaces from this code + * are not restricted to be used by modules with a GPL compatible license. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + * + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/spinlock.h> +#include <linux/rcupdate.h> +#include <linux/rculist.h> +#include <linux/net.h> +#include <linux/netdevice.h> +#include <linux/if_arp.h> +#include <linux/skbuff.h> +#include <linux/can.h> +#include <linux/can/core.h> +#include <linux/can/skb.h> +#include <linux/can/gw.h> +#include <net/rtnetlink.h> +#include <net/net_namespace.h> +#include <net/sock.h> + +#define CAN_GW_VERSION "20130117" +#define CAN_GW_NAME "can-gw" + +MODULE_DESCRIPTION("PF_CAN netlink gateway"); +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); +MODULE_ALIAS(CAN_GW_NAME); + +#define CGW_MIN_HOPS 1 +#define CGW_MAX_HOPS 6 +#define CGW_DEFAULT_HOPS 1 + +static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS; +module_param(max_hops, uint, S_IRUGO); +MODULE_PARM_DESC(max_hops, + "maximum " CAN_GW_NAME " routing hops for CAN frames " + "(valid values: " __stringify(CGW_MIN_HOPS) "-" + __stringify(CGW_MAX_HOPS) " hops, " + "default: " __stringify(CGW_DEFAULT_HOPS) ")"); + +static HLIST_HEAD(cgw_list); +static struct notifier_block notifier; + +static struct kmem_cache *cgw_cache __read_mostly; + +/* structure that contains the (on-the-fly) CAN frame modifications */ +struct cf_mod { + struct { + struct can_frame and; + struct can_frame or; + struct can_frame xor; + struct can_frame set; + } modframe; + struct { + u8 and; + u8 or; + u8 xor; + u8 set; + } modtype; + void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf, + struct cf_mod *mod); + + /* CAN frame checksum calculation after CAN frame modifications */ + struct { + struct cgw_csum_xor xor; + struct cgw_csum_crc8 crc8; + } csum; + struct { + void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor); + void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8); + } csumfunc; +}; + + +/* + * So far we just support CAN -> CAN routing and frame modifications. + * + * The internal can_can_gw structure contains data and attributes for + * a CAN -> CAN gateway job. + */ +struct can_can_gw { + struct can_filter filter; + int src_idx; + int dst_idx; +}; + +/* list entry for CAN gateways jobs */ +struct cgw_job { + struct hlist_node list; + struct rcu_head rcu; + u32 handled_frames; + u32 dropped_frames; + u32 deleted_frames; + struct cf_mod mod; + union { + /* CAN frame data source */ + struct net_device *dev; + } src; + union { + /* CAN frame data destination */ + struct net_device *dev; + } dst; + union { + struct can_can_gw ccgw; + /* tbc */ + }; + u8 gwtype; + u8 limit_hops; + u16 flags; +}; + +/* modification functions that are invoked in the hot path in can_can_gw_rcv */ + +#define MODFUNC(func, op) static void func(struct can_frame *cf, \ + struct cf_mod *mod) { op ; } + +MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id) +MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc) +MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data) +MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id) +MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc) +MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data) +MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id) +MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc) +MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data) +MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id) +MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc) +MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data) + +static inline void canframecpy(struct can_frame *dst, struct can_frame *src) +{ + /* + * Copy the struct members separately to ensure that no uninitialized + * data are copied in the 3 bytes hole of the struct. This is needed + * to make easy compares of the data in the struct cf_mod. + */ + + dst->can_id = src->can_id; + dst->can_dlc = src->can_dlc; + *(u64 *)dst->data = *(u64 *)src->data; +} + +static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re) +{ + /* + * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0] + * relative to received dlc -1 .. -8 : + * e.g. for received dlc = 8 + * -1 => index = 7 (data[7]) + * -3 => index = 5 (data[5]) + * -8 => index = 0 (data[0]) + */ + + if (fr > -9 && fr < 8 && + to > -9 && to < 8 && + re > -9 && re < 8) + return 0; + else + return -EINVAL; +} + +static inline int calc_idx(int idx, int rx_dlc) +{ + if (idx < 0) + return rx_dlc + idx; + else + return idx; +} + +static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor) +{ + int from = calc_idx(xor->from_idx, cf->can_dlc); + int to = calc_idx(xor->to_idx, cf->can_dlc); + int res = calc_idx(xor->result_idx, cf->can_dlc); + u8 val = xor->init_xor_val; + int i; + + if (from < 0 || to < 0 || res < 0) + return; + + if (from <= to) { + for (i = from; i <= to; i++) + val ^= cf->data[i]; + } else { + for (i = from; i >= to; i--) + val ^= cf->data[i]; + } + + cf->data[res] = val; +} + +static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor) +{ + u8 val = xor->init_xor_val; + int i; + + for (i = xor->from_idx; i <= xor->to_idx; i++) + val ^= cf->data[i]; + + cf->data[xor->result_idx] = val; +} + +static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor) +{ + u8 val = xor->init_xor_val; + int i; + + for (i = xor->from_idx; i >= xor->to_idx; i--) + val ^= cf->data[i]; + + cf->data[xor->result_idx] = val; +} + +static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8) +{ + int from = calc_idx(crc8->from_idx, cf->can_dlc); + int to = calc_idx(crc8->to_idx, cf->can_dlc); + int res = calc_idx(crc8->result_idx, cf->can_dlc); + u8 crc = crc8->init_crc_val; + int i; + + if (from < 0 || to < 0 || res < 0) + return; + + if (from <= to) { + for (i = crc8->from_idx; i <= crc8->to_idx; i++) + crc = crc8->crctab[crc^cf->data[i]]; + } else { + for (i = crc8->from_idx; i >= crc8->to_idx; i--) + crc = crc8->crctab[crc^cf->data[i]]; + } + + switch (crc8->profile) { + + case CGW_CRC8PRF_1U8: + crc = crc8->crctab[crc^crc8->profile_data[0]]; + break; + + case CGW_CRC8PRF_16U8: + crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; + break; + + case CGW_CRC8PRF_SFFID_XOR: + crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ + (cf->can_id >> 8 & 0xFF)]; + break; + + } + + cf->data[crc8->result_idx] = crc^crc8->final_xor_val; +} + +static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8) +{ + u8 crc = crc8->init_crc_val; + int i; + + for (i = crc8->from_idx; i <= crc8->to_idx; i++) + crc = crc8->crctab[crc^cf->data[i]]; + + switch (crc8->profile) { + + case CGW_CRC8PRF_1U8: + crc = crc8->crctab[crc^crc8->profile_data[0]]; + break; + + case CGW_CRC8PRF_16U8: + crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; + break; + + case CGW_CRC8PRF_SFFID_XOR: + crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ + (cf->can_id >> 8 & 0xFF)]; + break; + } + + cf->data[crc8->result_idx] = crc^crc8->final_xor_val; +} + +static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8) +{ + u8 crc = crc8->init_crc_val; + int i; + + for (i = crc8->from_idx; i >= crc8->to_idx; i--) + crc = crc8->crctab[crc^cf->data[i]]; + + switch (crc8->profile) { + + case CGW_CRC8PRF_1U8: + crc = crc8->crctab[crc^crc8->profile_data[0]]; + break; + + case CGW_CRC8PRF_16U8: + crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; + break; + + case CGW_CRC8PRF_SFFID_XOR: + crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ + (cf->can_id >> 8 & 0xFF)]; + break; + } + + cf->data[crc8->result_idx] = crc^crc8->final_xor_val; +} + +/* the receive & process & send function */ +static void can_can_gw_rcv(struct sk_buff *skb, void *data) +{ + struct cgw_job *gwj = (struct cgw_job *)data; + struct can_frame *cf; + struct sk_buff *nskb; + int modidx = 0; + + /* + * Do not handle CAN frames routed more than 'max_hops' times. + * In general we should never catch this delimiter which is intended + * to cover a misconfiguration protection (e.g. circular CAN routes). + * + * The Controller Area Network controllers only accept CAN frames with + * correct CRCs - which are not visible in the controller registers. + * According to skbuff.h documentation the csum_start element for IP + * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY. + * Only CAN skbs can be processed here which already have this property. + */ + +#define cgw_hops(skb) ((skb)->csum_start) + + BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY); + + if (cgw_hops(skb) >= max_hops) { + /* indicate deleted frames due to misconfiguration */ + gwj->deleted_frames++; + return; + } + + if (!(gwj->dst.dev->flags & IFF_UP)) { + gwj->dropped_frames++; + return; + } + + /* is sending the skb back to the incoming interface not allowed? */ + if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) && + can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex) + return; + + /* + * clone the given skb, which has not been done in can_rcv() + * + * When there is at least one modification function activated, + * we need to copy the skb as we want to modify skb->data. + */ + if (gwj->mod.modfunc[0]) + nskb = skb_copy(skb, GFP_ATOMIC); + else + nskb = skb_clone(skb, GFP_ATOMIC); + + if (!nskb) { + gwj->dropped_frames++; + return; + } + + /* put the incremented hop counter in the cloned skb */ + cgw_hops(nskb) = cgw_hops(skb) + 1; + + /* first processing of this CAN frame -> adjust to private hop limit */ + if (gwj->limit_hops && cgw_hops(nskb) == 1) + cgw_hops(nskb) = max_hops - gwj->limit_hops + 1; + + nskb->dev = gwj->dst.dev; + + /* pointer to modifiable CAN frame */ + cf = (struct can_frame *)nskb->data; + + /* perform preprocessed modification functions if there are any */ + while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx]) + (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod); + + /* check for checksum updates when the CAN frame has been modified */ + if (modidx) { + if (gwj->mod.csumfunc.crc8) + (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8); + + if (gwj->mod.csumfunc.xor) + (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor); + } + + /* clear the skb timestamp if not configured the other way */ + if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP)) + nskb->tstamp.tv64 = 0; + + /* send to netdevice */ + if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO)) + gwj->dropped_frames++; + else + gwj->handled_frames++; +} + +static inline int cgw_register_filter(struct cgw_job *gwj) +{ + return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id, + gwj->ccgw.filter.can_mask, can_can_gw_rcv, + gwj, "gw"); +} + +static inline void cgw_unregister_filter(struct cgw_job *gwj) +{ + can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id, + gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj); +} + +static int cgw_notifier(struct notifier_block *nb, + unsigned long msg, void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + + if (!net_eq(dev_net(dev), &init_net)) + return NOTIFY_DONE; + if (dev->type != ARPHRD_CAN) + return NOTIFY_DONE; + + if (msg == NETDEV_UNREGISTER) { + + struct cgw_job *gwj = NULL; + struct hlist_node *nx; + + ASSERT_RTNL(); + + hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { + + if (gwj->src.dev == dev || gwj->dst.dev == dev) { + hlist_del(&gwj->list); + cgw_unregister_filter(gwj); + kmem_cache_free(cgw_cache, gwj); + } + } + } + + return NOTIFY_DONE; +} + +static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type, + u32 pid, u32 seq, int flags) +{ + struct cgw_frame_mod mb; + struct rtcanmsg *rtcan; + struct nlmsghdr *nlh; + + nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags); + if (!nlh) + return -EMSGSIZE; + + rtcan = nlmsg_data(nlh); + rtcan->can_family = AF_CAN; + rtcan->gwtype = gwj->gwtype; + rtcan->flags = gwj->flags; + + /* add statistics if available */ + + if (gwj->handled_frames) { + if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0) + goto cancel; + } + + if (gwj->dropped_frames) { + if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0) + goto cancel; + } + + if (gwj->deleted_frames) { + if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0) + goto cancel; + } + + /* check non default settings of attributes */ + + if (gwj->limit_hops) { + if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0) + goto cancel; + } + + if (gwj->mod.modtype.and) { + memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); + mb.modtype = gwj->mod.modtype.and; + if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0) + goto cancel; + } + + if (gwj->mod.modtype.or) { + memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); + mb.modtype = gwj->mod.modtype.or; + if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0) + goto cancel; + } + + if (gwj->mod.modtype.xor) { + memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); + mb.modtype = gwj->mod.modtype.xor; + if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0) + goto cancel; + } + + if (gwj->mod.modtype.set) { + memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); + mb.modtype = gwj->mod.modtype.set; + if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0) + goto cancel; + } + + if (gwj->mod.csumfunc.crc8) { + if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN, + &gwj->mod.csum.crc8) < 0) + goto cancel; + } + + if (gwj->mod.csumfunc.xor) { + if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN, + &gwj->mod.csum.xor) < 0) + goto cancel; + } + + if (gwj->gwtype == CGW_TYPE_CAN_CAN) { + + if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) { + if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter), + &gwj->ccgw.filter) < 0) + goto cancel; + } + + if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0) + goto cancel; + + if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0) + goto cancel; + } + + nlmsg_end(skb, nlh); + return 0; + +cancel: + nlmsg_cancel(skb, nlh); + return -EMSGSIZE; +} + +/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */ +static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb) +{ + struct cgw_job *gwj = NULL; + int idx = 0; + int s_idx = cb->args[0]; + + rcu_read_lock(); + hlist_for_each_entry_rcu(gwj, &cgw_list, list) { + if (idx < s_idx) + goto cont; + + if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0) + break; +cont: + idx++; + } + rcu_read_unlock(); + + cb->args[0] = idx; + + return skb->len; +} + +static const struct nla_policy cgw_policy[CGW_MAX+1] = { + [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) }, + [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) }, + [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) }, + [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) }, + [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) }, + [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) }, + [CGW_SRC_IF] = { .type = NLA_U32 }, + [CGW_DST_IF] = { .type = NLA_U32 }, + [CGW_FILTER] = { .len = sizeof(struct can_filter) }, + [CGW_LIM_HOPS] = { .type = NLA_U8 }, +}; + +/* check for common and gwtype specific attributes */ +static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, + u8 gwtype, void *gwtypeattr, u8 *limhops) +{ + struct nlattr *tb[CGW_MAX+1]; + struct cgw_frame_mod mb; + int modidx = 0; + int err = 0; + + /* initialize modification & checksum data space */ + memset(mod, 0, sizeof(*mod)); + + err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, + cgw_policy); + if (err < 0) + return err; + + if (tb[CGW_LIM_HOPS]) { + *limhops = nla_get_u8(tb[CGW_LIM_HOPS]); + + if (*limhops < 1 || *limhops > max_hops) + return -EINVAL; + } + + /* check for AND/OR/XOR/SET modifications */ + + if (tb[CGW_MOD_AND]) { + nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN); + + canframecpy(&mod->modframe.and, &mb.cf); + mod->modtype.and = mb.modtype; + + if (mb.modtype & CGW_MOD_ID) + mod->modfunc[modidx++] = mod_and_id; + + if (mb.modtype & CGW_MOD_DLC) + mod->modfunc[modidx++] = mod_and_dlc; + + if (mb.modtype & CGW_MOD_DATA) + mod->modfunc[modidx++] = mod_and_data; + } + + if (tb[CGW_MOD_OR]) { + nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN); + + canframecpy(&mod->modframe.or, &mb.cf); + mod->modtype.or = mb.modtype; + + if (mb.modtype & CGW_MOD_ID) + mod->modfunc[modidx++] = mod_or_id; + + if (mb.modtype & CGW_MOD_DLC) + mod->modfunc[modidx++] = mod_or_dlc; + + if (mb.modtype & CGW_MOD_DATA) + mod->modfunc[modidx++] = mod_or_data; + } + + if (tb[CGW_MOD_XOR]) { + nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN); + + canframecpy(&mod->modframe.xor, &mb.cf); + mod->modtype.xor = mb.modtype; + + if (mb.modtype & CGW_MOD_ID) + mod->modfunc[modidx++] = mod_xor_id; + + if (mb.modtype & CGW_MOD_DLC) + mod->modfunc[modidx++] = mod_xor_dlc; + + if (mb.modtype & CGW_MOD_DATA) + mod->modfunc[modidx++] = mod_xor_data; + } + + if (tb[CGW_MOD_SET]) { + nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN); + + canframecpy(&mod->modframe.set, &mb.cf); + mod->modtype.set = mb.modtype; + + if (mb.modtype & CGW_MOD_ID) + mod->modfunc[modidx++] = mod_set_id; + + if (mb.modtype & CGW_MOD_DLC) + mod->modfunc[modidx++] = mod_set_dlc; + + if (mb.modtype & CGW_MOD_DATA) + mod->modfunc[modidx++] = mod_set_data; + } + + /* check for checksum operations after CAN frame modifications */ + if (modidx) { + + if (tb[CGW_CS_CRC8]) { + struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]); + + err = cgw_chk_csum_parms(c->from_idx, c->to_idx, + c->result_idx); + if (err) + return err; + + nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8], + CGW_CS_CRC8_LEN); + + /* + * select dedicated processing function to reduce + * runtime operations in receive hot path. + */ + if (c->from_idx < 0 || c->to_idx < 0 || + c->result_idx < 0) + mod->csumfunc.crc8 = cgw_csum_crc8_rel; + else if (c->from_idx <= c->to_idx) + mod->csumfunc.crc8 = cgw_csum_crc8_pos; + else + mod->csumfunc.crc8 = cgw_csum_crc8_neg; + } + + if (tb[CGW_CS_XOR]) { + struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]); + + err = cgw_chk_csum_parms(c->from_idx, c->to_idx, + c->result_idx); + if (err) + return err; + + nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR], + CGW_CS_XOR_LEN); + + /* + * select dedicated processing function to reduce + * runtime operations in receive hot path. + */ + if (c->from_idx < 0 || c->to_idx < 0 || + c->result_idx < 0) + mod->csumfunc.xor = cgw_csum_xor_rel; + else if (c->from_idx <= c->to_idx) + mod->csumfunc.xor = cgw_csum_xor_pos; + else + mod->csumfunc.xor = cgw_csum_xor_neg; + } + } + + if (gwtype == CGW_TYPE_CAN_CAN) { + + /* check CGW_TYPE_CAN_CAN specific attributes */ + + struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr; + memset(ccgw, 0, sizeof(*ccgw)); + + /* check for can_filter in attributes */ + if (tb[CGW_FILTER]) + nla_memcpy(&ccgw->filter, tb[CGW_FILTER], + sizeof(struct can_filter)); + + err = -ENODEV; + + /* specifying two interfaces is mandatory */ + if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF]) + return err; + + ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]); + ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]); + + /* both indices set to 0 for flushing all routing entries */ + if (!ccgw->src_idx && !ccgw->dst_idx) + return 0; + + /* only one index set to 0 is an error */ + if (!ccgw->src_idx || !ccgw->dst_idx) + return err; + } + + /* add the checks for other gwtypes here */ + + return 0; +} + +static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh) +{ + struct rtcanmsg *r; + struct cgw_job *gwj; + u8 limhops = 0; + int err = 0; + + if (!netlink_capable(skb, CAP_NET_ADMIN)) + return -EPERM; + + if (nlmsg_len(nlh) < sizeof(*r)) + return -EINVAL; + + r = nlmsg_data(nlh); + if (r->can_family != AF_CAN) + return -EPFNOSUPPORT; + + /* so far we only support CAN -> CAN routings */ + if (r->gwtype != CGW_TYPE_CAN_CAN) + return -EINVAL; + + gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL); + if (!gwj) + return -ENOMEM; + + gwj->handled_frames = 0; + gwj->dropped_frames = 0; + gwj->deleted_frames = 0; + gwj->flags = r->flags; + gwj->gwtype = r->gwtype; + + err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw, + &limhops); + if (err < 0) + goto out; + + err = -ENODEV; + + /* ifindex == 0 is not allowed for job creation */ + if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx) + goto out; + + gwj->src.dev = __dev_get_by_index(&init_net, gwj->ccgw.src_idx); + + if (!gwj->src.dev) + goto out; + + if (gwj->src.dev->type != ARPHRD_CAN) + goto out; + + gwj->dst.dev = __dev_get_by_index(&init_net, gwj->ccgw.dst_idx); + + if (!gwj->dst.dev) + goto out; + + if (gwj->dst.dev->type != ARPHRD_CAN) + goto out; + + gwj->limit_hops = limhops; + + ASSERT_RTNL(); + + err = cgw_register_filter(gwj); + if (!err) + hlist_add_head_rcu(&gwj->list, &cgw_list); +out: + if (err) + kmem_cache_free(cgw_cache, gwj); + + return err; +} + +static void cgw_remove_all_jobs(void) +{ + struct cgw_job *gwj = NULL; + struct hlist_node *nx; + + ASSERT_RTNL(); + + hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { + hlist_del(&gwj->list); + cgw_unregister_filter(gwj); + kmem_cache_free(cgw_cache, gwj); + } +} + +static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) +{ + struct cgw_job *gwj = NULL; + struct hlist_node *nx; + struct rtcanmsg *r; + struct cf_mod mod; + struct can_can_gw ccgw; + u8 limhops = 0; + int err = 0; + + if (!netlink_capable(skb, CAP_NET_ADMIN)) + return -EPERM; + + if (nlmsg_len(nlh) < sizeof(*r)) + return -EINVAL; + + r = nlmsg_data(nlh); + if (r->can_family != AF_CAN) + return -EPFNOSUPPORT; + + /* so far we only support CAN -> CAN routings */ + if (r->gwtype != CGW_TYPE_CAN_CAN) + return -EINVAL; + + err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops); + if (err < 0) + return err; + + /* two interface indices both set to 0 => remove all entries */ + if (!ccgw.src_idx && !ccgw.dst_idx) { + cgw_remove_all_jobs(); + return 0; + } + + err = -EINVAL; + + ASSERT_RTNL(); + + /* remove only the first matching entry */ + hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { + + if (gwj->flags != r->flags) + continue; + + if (gwj->limit_hops != limhops) + continue; + + if (memcmp(&gwj->mod, &mod, sizeof(mod))) + continue; + + /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */ + if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) + continue; + + hlist_del(&gwj->list); + cgw_unregister_filter(gwj); + kmem_cache_free(cgw_cache, gwj); + err = 0; + break; + } + + return err; +} + +static __init int cgw_module_init(void) +{ + /* sanitize given module parameter */ + max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS); + + pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n", + max_hops); + + cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job), + 0, 0, NULL); + + if (!cgw_cache) + return -ENOMEM; + + /* set notifier */ + notifier.notifier_call = cgw_notifier; + register_netdevice_notifier(¬ifier); + + if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) { + unregister_netdevice_notifier(¬ifier); + kmem_cache_destroy(cgw_cache); + return -ENOBUFS; + } + + /* Only the first call to __rtnl_register can fail */ + __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL); + __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL); + + return 0; +} + +static __exit void cgw_module_exit(void) +{ + rtnl_unregister_all(PF_CAN); + + unregister_netdevice_notifier(¬ifier); + + rtnl_lock(); + cgw_remove_all_jobs(); + rtnl_unlock(); + + rcu_barrier(); /* Wait for completion of call_rcu()'s */ + + kmem_cache_destroy(cgw_cache); +} + +module_init(cgw_module_init); +module_exit(cgw_module_exit); |