can: gw: add support for CAN FD frames

Introduce CAN FD support which needs an extension of the netlink API to
pass CAN FD type content to the kernel which has a different size to
Classic CAN. Additionally the struct canfd_frame has a new 'flags' element
that can now be modified with can-gw.

The new CGW_FLAGS_CAN_FD option flag defines whether the routing job
handles Classic CAN or CAN FD frames. This setting is very strict at
reception time and enables the new possibilities, e.g. CGW_FDMOD_* and
modifying the flags element of struct canfd_frame, only when
CGW_FLAGS_CAN_FD is set.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/include/uapi/linux/can/gw.h b/include/uapi/linux/can/gw.h
index ed811bc463b51ea59c365a908fad895616b0b061..3aea5388c8e4782d86f4e18d05671251596b54b4 100644 (file)
--- a/include/uapi/linux/can/gw.h
+++ b/include/uapi/linux/can/gw.h
@@ -80,6 +80,10 @@ enum {
        CGW_DELETED,    /* number of deleted CAN frames (see max_hops param) */
        CGW_LIM_HOPS,   /* limit the number of hops of this specific rule */
        CGW_MOD_UID,    /* user defined identifier for modification updates */
+       CGW_FDMOD_AND,  /* CAN FD frame modification binary AND */
+       CGW_FDMOD_OR,   /* CAN FD frame modification binary OR */
+       CGW_FDMOD_XOR,  /* CAN FD frame modification binary XOR */
+       CGW_FDMOD_SET,  /* CAN FD frame modification set alternate values */
        __CGW_MAX
 };
 
@@ -88,6 +92,7 @@ enum {
 #define CGW_FLAGS_CAN_ECHO 0x01
 #define CGW_FLAGS_CAN_SRC_TSTAMP 0x02
 #define CGW_FLAGS_CAN_IIF_TX_OK 0x04
+#define CGW_FLAGS_CAN_FD 0x08
 
 #define CGW_MOD_FUNCS 4 /* AND OR XOR SET */
 
@@ -96,8 +101,9 @@ enum {
 #define CGW_MOD_DLC    0x02            /* contains the data length in bytes */
 #define CGW_MOD_LEN    CGW_MOD_DLC     /* CAN FD length representation */
 #define CGW_MOD_DATA   0x04
+#define CGW_MOD_FLAGS  0x08            /* CAN FD flags */
 
-#define CGW_FRAME_MODS 3 /* ID DLC/LEN DATA */
+#define CGW_FRAME_MODS 4 /* ID DLC/LEN DATA FLAGS */
 
 #define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS)
 
@@ -106,7 +112,13 @@ struct cgw_frame_mod {
        __u8 modtype;
 } __attribute__((packed));
 
+struct cgw_fdframe_mod {
+       struct canfd_frame cf;
+       __u8 modtype;
+} __attribute__((packed));
+
 #define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod)
+#define CGW_FDMODATTR_LEN sizeof(struct cgw_fdframe_mod)
 
 struct cgw_csum_xor {
        __s8 from_idx;

diff --git a/net/can/gw.c b/net/can/gw.c
index 3a1ad206fbef2ff40df35bf7fc646d40547b679b..65d60c93af2945e7a28fae8333db344bfcbe120b 100644 (file)
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
 /* gw.c - CAN frame Gateway/Router/Bridge with netlink interface
  *
- * Copyright (c) 2017 Volkswagen Group Electronic Research
+ * Copyright (c) 2019 Volkswagen Group Electronic Research
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -59,7 +59,7 @@
 #include <net/net_namespace.h>
 #include <net/sock.h>
 
-#define CAN_GW_VERSION "20170425"
+#define CAN_GW_VERSION "20190810"
 #define CAN_GW_NAME "can-gw"
 
 MODULE_DESCRIPTION("PF_CAN netlink gateway");
@@ -156,17 +156,50 @@ struct cgw_job {
 
 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
 MODFUNC(mod_and_len, cf->len &= mod->modframe.and.len)
+MODFUNC(mod_and_flags, cf->flags &= mod->modframe.and.flags)
 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_len, cf->len |= mod->modframe.or.len)
+MODFUNC(mod_or_flags, cf->flags |= mod->modframe.or.flags)
 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_len, cf->len ^= mod->modframe.xor.len)
+MODFUNC(mod_xor_flags, cf->flags ^= mod->modframe.xor.flags)
 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_len, cf->len = mod->modframe.set.len)
+MODFUNC(mod_set_flags, cf->flags = mod->modframe.set.flags)
 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
 
+static void mod_and_fddata(struct canfd_frame *cf, struct cf_mod *mod)
+{
+       int i;
+
+       for (i = 0; i < CANFD_MAX_DLEN; i += 8)
+               *(u64 *)(cf->data + i) &= *(u64 *)(mod->modframe.and.data + i);
+}
+
+static void mod_or_fddata(struct canfd_frame *cf, struct cf_mod *mod)
+{
+       int i;
+
+       for (i = 0; i < CANFD_MAX_DLEN; i += 8)
+               *(u64 *)(cf->data + i) |= *(u64 *)(mod->modframe.or.data + i);
+}
+
+static void mod_xor_fddata(struct canfd_frame *cf, struct cf_mod *mod)
+{
+       int i;
+
+       for (i = 0; i < CANFD_MAX_DLEN; i += 8)
+               *(u64 *)(cf->data + i) ^= *(u64 *)(mod->modframe.xor.data + i);
+}
+
+static void mod_set_fddata(struct canfd_frame *cf, struct cf_mod *mod)
+{
+       memcpy(cf->data, mod->modframe.set.data, CANFD_MAX_DLEN);
+}
+
 static void canframecpy(struct canfd_frame *dst, struct can_frame *src)
 {
        /* Copy the struct members separately to ensure that no uninitialized
@@ -179,10 +212,26 @@ static void canframecpy(struct canfd_frame *dst, struct can_frame *src)
        *(u64 *)dst->data = *(u64 *)src->data;
 }
 
-static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
+static void canfdframecpy(struct canfd_frame *dst, struct canfd_frame *src)
+{
+       /* Copy the struct members separately to ensure that no uninitialized
+        * data are copied in the 2 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->flags = src->flags;
+       dst->len = src->len;
+       memcpy(dst->data, src->data, CANFD_MAX_DLEN);
+}
+
+static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re, struct rtcanmsg *r)
 {
        s8 dlen = CAN_MAX_DLEN;
 
+       if (r->flags & CGW_FLAGS_CAN_FD)
+               dlen = CANFD_MAX_DLEN;
+
        /* absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
         * relative to received dlc -1 .. -8 :
         * e.g. for received dlc = 8
@@ -351,6 +400,15 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
        struct sk_buff *nskb;
        int modidx = 0;
 
+       /* process strictly Classic CAN or CAN FD frames */
+       if (gwj->flags & CGW_FLAGS_CAN_FD) {
+               if (skb->len != CANFD_MTU)
+                       return;
+       } else {
+               if (skb->len != CAN_MTU)
+                       return;
+       }
+
        /* 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).
@@ -419,23 +477,19 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
                int max_len = nskb->len - offsetof(struct canfd_frame, data);
 
                /* dlc may have changed, make sure it fits to the CAN frame */
-               if (cf->len > max_len)
-                       goto out_delete;
-
-               /* check for checksum updates in classic CAN length only */
-               if (gwj->mod.csumfunc.crc8) {
-                       if (cf->len > 8)
-                               goto out_delete;
-
-                       (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
+               if (cf->len > max_len) {
+                       /* delete frame due to misconfiguration */
+                       gwj->deleted_frames++;
+                       kfree_skb(nskb);
+                       return;
                }
 
-               if (gwj->mod.csumfunc.xor) {
-                       if (cf->len > 8)
-                               goto out_delete;
+               /* check for checksum updates */
+               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 */
@@ -447,13 +501,6 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
                gwj->dropped_frames++;
        else
                gwj->handled_frames++;
-
-       return;
-
- out_delete:
-       /* delete frame due to misconfiguration */
-       gwj->deleted_frames++;
-       kfree_skb(nskb);
 }
 
 static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
@@ -535,7 +582,37 @@ static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
                        goto cancel;
        }
 
-       if (1) {
+       if (gwj->flags & CGW_FLAGS_CAN_FD) {
+               struct cgw_fdframe_mod mb;
+
+               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_FDMOD_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_FDMOD_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_FDMOD_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_FDMOD_SET, sizeof(mb), &mb) < 0)
+                               goto cancel;
+               }
+       } else {
                struct cgw_frame_mod mb;
 
                if (gwj->mod.modtype.and) {
@@ -645,6 +722,10 @@ static const struct nla_policy cgw_policy[CGW_MAX + 1] = {
        [CGW_FILTER]    = { .len = sizeof(struct can_filter) },
        [CGW_LIM_HOPS]  = { .type = NLA_U8 },
        [CGW_MOD_UID]   = { .type = NLA_U32 },
+       [CGW_FDMOD_AND] = { .len = sizeof(struct cgw_fdframe_mod) },
+       [CGW_FDMOD_OR]  = { .len = sizeof(struct cgw_fdframe_mod) },
+       [CGW_FDMOD_XOR] = { .len = sizeof(struct cgw_fdframe_mod) },
+       [CGW_FDMOD_SET] = { .len = sizeof(struct cgw_fdframe_mod) },
 };
 
 /* check for common and gwtype specific attributes */
@@ -652,6 +733,7 @@ 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 rtcanmsg *r = nlmsg_data(nlh);
        int modidx = 0;
        int err = 0;
 
@@ -671,7 +753,85 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
        }
 
        /* check for AND/OR/XOR/SET modifications */
-       if (1) {
+       if (r->flags & CGW_FLAGS_CAN_FD) {
+               struct cgw_fdframe_mod mb;
+
+               if (tb[CGW_FDMOD_AND]) {
+                       nla_memcpy(&mb, tb[CGW_FDMOD_AND], CGW_FDMODATTR_LEN);
+
+                       canfdframecpy(&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_LEN)
+                               mod->modfunc[modidx++] = mod_and_len;
+
+                       if (mb.modtype & CGW_MOD_FLAGS)
+                               mod->modfunc[modidx++] = mod_and_flags;
+
+                       if (mb.modtype & CGW_MOD_DATA)
+                               mod->modfunc[modidx++] = mod_and_fddata;
+               }
+
+               if (tb[CGW_FDMOD_OR]) {
+                       nla_memcpy(&mb, tb[CGW_FDMOD_OR], CGW_FDMODATTR_LEN);
+
+                       canfdframecpy(&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_LEN)
+                               mod->modfunc[modidx++] = mod_or_len;
+
+                       if (mb.modtype & CGW_MOD_FLAGS)
+                               mod->modfunc[modidx++] = mod_or_flags;
+
+                       if (mb.modtype & CGW_MOD_DATA)
+                               mod->modfunc[modidx++] = mod_or_fddata;
+               }
+
+               if (tb[CGW_FDMOD_XOR]) {
+                       nla_memcpy(&mb, tb[CGW_FDMOD_XOR], CGW_FDMODATTR_LEN);
+
+                       canfdframecpy(&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_LEN)
+                               mod->modfunc[modidx++] = mod_xor_len;
+
+                       if (mb.modtype & CGW_MOD_FLAGS)
+                               mod->modfunc[modidx++] = mod_xor_flags;
+
+                       if (mb.modtype & CGW_MOD_DATA)
+                               mod->modfunc[modidx++] = mod_xor_fddata;
+               }
+
+               if (tb[CGW_FDMOD_SET]) {
+                       nla_memcpy(&mb, tb[CGW_FDMOD_SET], CGW_FDMODATTR_LEN);
+
+                       canfdframecpy(&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_LEN)
+                               mod->modfunc[modidx++] = mod_set_len;
+
+                       if (mb.modtype & CGW_MOD_FLAGS)
+                               mod->modfunc[modidx++] = mod_set_flags;
+
+                       if (mb.modtype & CGW_MOD_DATA)
+                               mod->modfunc[modidx++] = mod_set_fddata;
+               }
+       } else {
                struct cgw_frame_mod mb;
 
                if (tb[CGW_MOD_AND]) {
@@ -745,7 +905,7 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
                        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);
+                                                c->result_idx, r);
                        if (err)
                                return err;
 
@@ -768,7 +928,7 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
                        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);
+                                                c->result_idx, r);
                        if (err)
                                return err;