diff options
| -rw-r--r-- | include/uapi/linux/can/gw.h | 9 | ||||
| -rw-r--r-- | net/can/gw.c | 35 |
2 files changed, 39 insertions, 5 deletions
diff --git a/include/uapi/linux/can/gw.h b/include/uapi/linux/can/gw.h index ae07bec74f4b..4e27c82b564a 100644 --- a/include/uapi/linux/can/gw.h +++ b/include/uapi/linux/can/gw.h @@ -45,6 +45,7 @@ enum { CGW_DST_IF, /* ifindex of destination network interface */ CGW_FILTER, /* specify struct can_filter on source CAN device */ CGW_DELETED, /* number of deleted CAN frames (see max_hops param) */ + CGW_LIM_HOPS, /* limit the number of hops of this specific rule */ __CGW_MAX }; @@ -116,13 +117,19 @@ enum { * Sets a CAN receive filter for the gateway job specified by the * struct can_filter described in include/linux/can.h * - * CGW_MOD_XXX (length 17 bytes): + * CGW_MOD_(AND|OR|XOR|SET) (length 17 bytes): * Specifies a modification that's done to a received CAN frame before it is * send out to the destination interface. * * <struct can_frame> data used as operator * <u8> affected CAN frame elements * + * CGW_LIM_HOPS (length 1 byte): + * Limit the number of hops of this specific rule. Usually the received CAN + * frame can be processed as much as 'max_hops' times (which is given at module + * load time of the can-gw module). This value is used to reduce the number of + * possible hops for this gateway rule to a value smaller then max_hops. + * * CGW_CS_XOR (length 4 bytes): * Set a simple XOR checksum starting with an initial value into * data[result-idx] using data[start-idx] .. data[end-idx] diff --git a/net/can/gw.c b/net/can/gw.c index 2f291f961a17..3f9b0f3a2818 100644 --- a/net/can/gw.c +++ b/net/can/gw.c @@ -146,6 +146,7 @@ struct cgw_job { /* tbc */ }; u8 gwtype; + u8 limit_hops; u16 flags; }; @@ -402,6 +403,11 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data) /* 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 */ @@ -509,6 +515,11 @@ static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type, /* 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; @@ -606,11 +617,12 @@ static const struct nla_policy cgw_policy[CGW_MAX+1] = { [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 gwtype, void *gwtypeattr, u8 *limhops) { struct nlattr *tb[CGW_MAX+1]; struct cgw_frame_mod mb; @@ -625,6 +637,13 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 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]) { @@ -782,6 +801,7 @@ 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 (!capable(CAP_NET_ADMIN)) @@ -808,7 +828,8 @@ static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh) gwj->flags = r->flags; gwj->gwtype = r->gwtype; - err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw); + err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw, + &limhops); if (err < 0) goto out; @@ -836,6 +857,8 @@ static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh) if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops) goto put_src_dst_out; + gwj->limit_hops = limhops; + ASSERT_RTNL(); err = cgw_register_filter(gwj); @@ -867,13 +890,14 @@ static void cgw_remove_all_jobs(void) } } -static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) +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 (!capable(CAP_NET_ADMIN)) @@ -890,7 +914,7 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) if (r->gwtype != CGW_TYPE_CAN_CAN) return -EINVAL; - err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw); + err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops); if (err < 0) return err; @@ -910,6 +934,9 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) if (gwj->flags != r->flags) continue; + if (gwj->limit_hops != limhops) + continue; + if (memcmp(&gwj->mod, &mod, sizeof(mod))) continue; |