Re: [B.A.T.M.A.N.] [PATCHv3 3/3] batman-adv: improved gateway tq-based selection

If a client issues a DHCPREQUEST for renewal, the packet is dropped if the old destination (the old gateway for the client) TQ is smaller than the current best gateway TQ less GW_THRESHOLD Signed-off-by: Antonio Quartulli &lt;ordex(a)autistici.org&gt; --- gateway_client.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++- gateway_client.h | 3 +- main.h | 3 +- soft-interface.c | 10 ++++- 4 files changed, 104 insertions(+), 6 deletions(-) diff --git a/gateway_client.c b/gateway_client.c index 761dcfb..33bceee 100644 --- a/gateway_client.c +++ b/gateway_client.c @@ -25,11 +25,17 @@ #include "gateway_common.h" #include "hard-interface.h" #include "originator.h" +#include "routing.h" #include <linux/ip.h> #include <linux/ipv6.h> #include <linux/udp.h> #include <linux/if_vlan.h> +/* This is the offset of the options field in a dhcp packet starting at + * the beginning of the dhcp header */ +#define DHCP_OPTIONS_OFFSET 240 +#define DHCP_REQUEST 3 + static void gw_node_free_rcu(struct rcu_head *rcu) { struct gw_node *gw_node; @@ -509,14 +515,75 @@ out: return ret; } -int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb) +static bool is_type_dhcprequest(struct sk_buff *skb, int header_len) +{ + int ret = false; + unsigned char *p; + int pkt_len; + + if (skb_linearize(skb) < 0) + goto out; + + pkt_len = skb_headlen(skb); + + if (pkt_len < header_len + DHCP_OPTIONS_OFFSET + 1) + goto out; + + p = skb->data + header_len + DHCP_OPTIONS_OFFSET; + pkt_len -= header_len + DHCP_OPTIONS_OFFSET + 1; + + /* Access the dhcp option lists. Each entry is made up by: + * - octect 1: option type + * - octect 2: option data len (only if type != 255 and 0) + * - octect 3: option data */ + while (*p != 255 && !ret) { + /* p now points to the first octect: option type */ + if (*p == 53) { + /* type 53 is the message type option. + * Jump the len octect and go to the data octect */ + if (pkt_len < 2) + goto out; + pkt_len -= 2; + p += 2; + + /* check if the message type is what we need */ + if (*p == DHCP_REQUEST) + ret = true;