From patchwork Sun Oct 30 08:56:00 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antonio Quartulli X-Patchwork-Id: 1317 Return-Path: Received: from confino.investici.org (investici.nine.ch [217.150.252.179]) by open-mesh.org (Postfix) with ESMTPS id F1A8B600749 for ; Sun, 30 Oct 2011 09:57:16 +0100 (CET) Authentication-Results: open-mesh.org; dkim=pass (1024-bit key) header.i=@autistici.org; dkim-adsp=pass Received: from [217.150.252.179] (confino [217.150.252.179]) (Authenticated sender: ordex@autistici.org) by localhost (Postfix) with ESMTPSA id 486F4C8648; Sun, 30 Oct 2011 08:57:16 +0000 (UTC) X-DKIM: Sendmail DKIM Filter v2.8.2 confino.investici.org 486F4C8648 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=autistici.org; s=stigmate; t=1319965036; bh=R42S14Xa+/i9sLNur1LCHxIphXkKBgssEk9RJOQqOHU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=RAKdmJalhLoPo6pUHL/Nu9LvW0VlvmQ63nPuFP5oJZM7xKd8idbkmj2Y3sU8ukGXs EegiZg/FC8WnRU01xzUECrAwYen216T5fA5Zl60JxKHmoPe8vZwi23h0nVOixruvNW Gm4PjkRVsBhxAw0GHkd3y1BX1Kqye4OuRb7Bn6C0= From: Antonio Quartulli To: b.a.t.m.a.n@lists.open-mesh.org Date: Sun, 30 Oct 2011 09:56:00 +0100 Message-Id: <1319964962-5092-5-git-send-email-ordex@autistici.org> X-Mailer: git-send-email 1.7.3.4 In-Reply-To: <1319964962-5092-1-git-send-email-ordex@autistici.org> References: <1319964962-5092-1-git-send-email-ordex@autistici.org> Subject: [B.A.T.M.A.N.] [PATCH 4/6] batman-adv: Distributed ARP Table - add ARP parsing functions X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.13 Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Oct 2011 08:57:17 -0000 ARP messages are now parsed to make it possible to trigger special actions depending on their types (snooping). Signed-off-by: Antonio Quartulli --- arp.c | 43 +++++++++++++++++++++++++++++++++++++++++++ arp.h | 7 +++++++ 2 files changed, 50 insertions(+), 0 deletions(-) diff --git a/arp.c b/arp.c index 39043b8..ea7cc1e 100644 --- a/arp.c +++ b/arp.c @@ -183,3 +183,46 @@ out: kfree(cand); return ret; } + +/* Returns arphdr->ar_op if the skb contains a valid ARP packet, otherwise + * returns 0 */ +uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb) +{ + struct arphdr *arphdr; + struct ethhdr *ethhdr; + uint16_t type = 0; + + if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) + goto out; + + ethhdr = (struct ethhdr *)skb_mac_header(skb); + + if (ethhdr->h_proto != htons(ETH_P_ARP)) + goto out; + + if (unlikely(!pskb_may_pull(skb, ETH_HLEN + arp_hdr_len(skb->dev) + 8 + 12))) + goto out; + + arphdr = (struct arphdr *)(skb->data + sizeof(struct ethhdr)); + + /* Check whether the ARP packet carries a valid + * IP information */ + if (arphdr->ar_hrd != htons(ARPHRD_ETHER)) + goto out; + + if (arphdr->ar_pro != htons(ETH_P_IP)) + goto out; + + if (arphdr->ar_hln != ETH_ALEN) + goto out; + + if (arphdr->ar_pln != 4) + goto out; + + type = ntohs(arphdr->ar_op); + bat_dbg(DBG_ARP, bat_priv, "ARP message of type %d recognised " + "[%pM-%pI4 %pM-%pI4]\n", type, ARP_HW_SRC(skb), + &ARP_IP_SRC(skb), ARP_HW_DST(skb), &ARP_IP_DST(skb)); +out: + return type; +} diff --git a/arp.h b/arp.h index ee1a8b3..56b0a0a 100644 --- a/arp.h +++ b/arp.h @@ -22,6 +22,13 @@ #ifndef _NET_BATMAN_ADV_ARP_H_ #define _NET_BATMAN_ADV_ARP_H_ +#define ARP_HW_SRC(skb) ((uint8_t *)(skb->data) + sizeof(struct ethhdr) + sizeof(struct arphdr)) +#define ARP_IP_SRC(skb) (*(uint32_t *)(ARP_HW_SRC(skb) + ETH_ALEN)) +#define ARP_HW_DST(skb) (ARP_HW_SRC(skb) + ETH_ALEN + 4) +#define ARP_IP_DST(skb) (*(uint32_t *)(ARP_HW_SRC(skb) + ETH_ALEN * 2 + 4)) + +uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb); + /* hash function to choose an entry in a hash table of given size */ /* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */ static inline uint32_t hash_ipv4(const void *data, uint32_t size)