Beautify check for valid CAN netdevices.

[socketcan-devel.git] / kernel / 2.6 / net / can / gw.c

diff --git a/kernel/2.6/net/can/gw.c b/kernel/2.6/net/can/gw.c
index e512427c697c7715a559a3f39f9a518c711ac1fc..d7257ccbcb1439336914242d8991f5e9a4512659 100644 (file)
--- a/kernel/2.6/net/can/gw.c
+++ b/kernel/2.6/net/can/gw.c
@@ -1,7 +1,7 @@
 /*
  * gw.c - CAN frame Gateway/Router/Bridge with netlink interface
  *
- * Copyright (c) 2002-2010 Volkswagen Group Electronic Research
+ * Copyright (c) 2011 Volkswagen Group Electronic Research
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -58,11 +58,12 @@
 #include <socketcan/can/gw.h>
 #include <net/rtnetlink.h>
 #include <net/net_namespace.h>
+#include <net/sock.h>
 
 #include <socketcan/can/version.h> /* for RCSID. Removed by mkpatch script */
 RCSID("$Id$");
 
-#define CAN_GW_VERSION "20101205"
+#define CAN_GW_VERSION "20101209"
 static __initdata const char banner[] =
        KERN_INFO "can: netlink gateway (rev " CAN_GW_VERSION ")\n";
 
@@ -76,8 +77,6 @@ static struct notifier_block notifier;
 
 static struct kmem_cache *cgw_cache __read_mostly;
 
-#define CGW_SK_MAGIC ((void *)(&notifier))
-
 /* structure that contains the (on-the-fly) CAN frame modifications */
 struct cf_mod {
        struct {
@@ -144,8 +143,8 @@ struct cgw_job {
 
 /* 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 ; }
+#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)
@@ -175,10 +174,10 @@ static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
 
 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 
+        * e.g. for received dlc = 8
         * -1 => index = 7 (data[7])
         * -3 => index = 5 (data[5])
         * -8 => index = 0 (data[0])
@@ -190,7 +189,7 @@ static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
                return 0;
        else
                return -EINVAL;
-} 
+}
 
 static inline int calc_idx(int idx, int rx_dlc)
 {
@@ -213,10 +212,10 @@ static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
 
        if (from <= to) {
                for (i = from; i <= to; i++)
-                       val ^= cf->data[i]; 
+                       val ^= cf->data[i];
        } else {
                for (i = from; i >= to; i--)
-                       val ^= cf->data[i]; 
+                       val ^= cf->data[i];
        }
 
        cf->data[res] = val;
@@ -345,8 +344,8 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
        struct sk_buff *nskb;
        int modidx = 0;
 
-       /* do not handle already routed frames */
-       if (skb->sk == CGW_SK_MAGIC)
+       /* do not handle already routed frames - see comment below */
+       if (skb_mac_header_was_set(skb))
                return;
 
        if (!(gwj->dst.dev->flags & IFF_UP)) {
@@ -370,8 +369,15 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
                return;
        }
 
-       /* mark routed frames with a 'special' sk value */
-       nskb->sk = CGW_SK_MAGIC;
+       /*
+        * Mark routed frames by setting some mac header length which is
+        * not relevant for the CAN frames located in the skb->data section.
+        *
+        * As dev->header_ops is not set in CAN netdevices no one is ever
+        * accessing the various header offsets in the CAN skbuffs anyway.
+        * E.g. using the packet socket to read CAN frames is still working.
+        */
+       skb_set_mac_header(nskb, 8);
        nskb->dev = gwj->dst.dev;
 
        /* pointer to modifiable CAN frame */
@@ -438,7 +444,7 @@ static int cgw_notifier(struct notifier_block *nb,
 
                hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
 
-                       if (gwj->src.dev == dev || gwj->dst.dev == dev) { 
+                       if (gwj->src.dev == dev || gwj->dst.dev == dev) {
                                hlist_del(&gwj->list);
                                cgw_unregister_filter(gwj);
                                kfree(gwj);
@@ -589,7 +595,7 @@ cont:
 }
 
 /* check for common and gwtype specific attributes */
-static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 
+static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
                          u8 gwtype, void *gwtypeattr)
 {
        struct nlattr *tb[CGW_MAX+1];
@@ -598,7 +604,7 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
        int err = 0;
 
        /* initialize modification & checksum data space */
-       memset(mod, 0, sizeof(*mod)); 
+       memset(mod, 0, sizeof(*mod));
 
        err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, NULL);
        if (err < 0)
@@ -737,7 +743,7 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
                /* check CGW_TYPE_CAN_CAN specific attributes */
 
                struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
-               memset(ccgw, 0, sizeof(*ccgw)); 
+               memset(ccgw, 0, sizeof(*ccgw));
 
                /* check for can_filter in attributes */
                if (tb[CGW_FILTER] &&
@@ -815,7 +821,8 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
        if (!gwj->src.dev)
                goto out;
 
-       if (gwj->src.dev->type != ARPHRD_CAN)
+       /* check for CAN netdev not using header_ops - see gw_rcv() */
+       if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops)
                goto put_src_out;
 
        gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
@@ -823,9 +830,10 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
        if (!gwj->dst.dev)
                goto put_src_out;
 
-       if (gwj->dst.dev->type != ARPHRD_CAN)
+       /* check for CAN netdev not using header_ops - see gw_rcv() */
+       if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops)
                goto put_src_dst_out;
-               
+
        ASSERT_RTNL();
 
        err = cgw_register_filter(gwj);