Andrew Lunn schrieb:
- uint8_t rr[BAT_RR_LEN];
This might be more readable as
uint8_t rr[BAT_RR_ENTRIES][ETH_ALEN];
and then your memcpy becomes
/* add record route information if not full */ if (icmp_packet->rr_cur < BAT_RR_ENTRIES) { memcpy(icmp_packet->rr[icmp_packet->rr_cur++], ethhdr->h_dest, ETH_ALEN); }
You're right, this makes things easier => changed.
ssize_t bat_device_write(struct file *file, const char __user *buff, @@ -206,28 +210,42 @@ { struct device_client *device_client = (struct device_client *)file->private_data;
- struct icmp_packet icmp_packet;
struct icmp_packet_rr icmp_packet; struct orig_node *orig_node; struct batman_if *batman_if; uint8_t dstaddr[ETH_ALEN]; unsigned long flags;
size_t packet_len = sizeof(struct icmp_packet);
int with_rr = 0;
if (len < sizeof(struct icmp_packet)) { bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: invalid packet size\n"); return -EINVAL; }
- if (!access_ok(VERIFY_READ, buff, sizeof(struct icmp_packet)))
- if (len >= sizeof(struct icmp_packet_rr)) {
At first look, this looks wrong. I would of expected icmp_packet, not icmp_packet_rr. But maybe it is right?
It is right: At this point, the program doesn't know whether an icmp_packet or an icmp_packet_rr is written. However, it can distinguish these two by looking at the length of the data: if len >= sizeof(struct icmp_packet_rr), the packet is long enough to include RR info and is therefore treated as such.
int recv_icmp_packet(struct sk_buff *skb) {
- struct icmp_packet *icmp_packet;
- struct icmp_packet_rr *icmp_packet; struct ethhdr *ethhdr; struct orig_node *orig_node; struct sk_buff *skb_old;
@@ -860,8 +868,24 @@ if (!is_my_mac(ethhdr->h_dest)) return NET_RX_DROP;
- icmp_packet = (struct icmp_packet *) skb->data;
icmp_packet = (struct icmp_packet_rr *) skb->data;
if (icmp_packet->packet_type == BAT_ICMP_RR) {
hdr_size = sizeof(struct icmp_packet_rr);/* drop packet if it has not necessary minimum size */if (skb_headlen(skb) < hdr_size)return NET_RX_DROP;/* add record route information if not full */if (icmp_packet->rr_cur > 0&& icmp_packet->rr_cur < BAT_RR_LEN / ETH_ALEN) {memcpy(&(icmp_packet->rr[icmp_packet->rr_cur * ETH_ALEN]),ethhdr->h_dest, ETH_ALEN);Why rr_cur > 0?
For historical reasons ;-) rr_cur generally is the index for rr that indicates the next position to be written to. In the first version of the patch, a value of 0 for rr_cur indicated that RR is not active. This is no longer neccessary => changed. Thanks for pointing out.
Regards, Daniel