diff options
| -rw-r--r-- | net/batman-adv/distributed-arp-table.c | 399 | ||||
| -rw-r--r-- | net/batman-adv/distributed-arp-table.h | 19 | ||||
| -rw-r--r-- | net/batman-adv/routing.c | 4 | ||||
| -rw-r--r-- | net/batman-adv/soft-interface.c | 11 |
4 files changed, 431 insertions, 2 deletions
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c index b9ffe1826527..c7f3e2231233 100644 --- a/net/batman-adv/distributed-arp-table.c +++ b/net/batman-adv/distributed-arp-table.c @@ -19,6 +19,7 @@ #include "distributed-arp-table.h" #include "main.h" +#include <asm/unaligned.h> #include <linux/atomic.h> #include <linux/bitops.h> #include <linux/byteorder/generic.h> @@ -29,6 +30,7 @@ #include <linux/if_ether.h> #include <linux/if_vlan.h> #include <linux/in.h> +#include <linux/ip.h> #include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/kref.h> @@ -42,6 +44,7 @@ #include <linux/spinlock.h> #include <linux/stddef.h> #include <linux/string.h> +#include <linux/udp.h> #include <linux/workqueue.h> #include <net/arp.h> #include <net/genetlink.h> @@ -60,6 +63,49 @@ #include "translation-table.h" #include "tvlv.h" +enum batadv_bootpop { + BATADV_BOOTREPLY = 2, +}; + +enum batadv_boothtype { + BATADV_HTYPE_ETHERNET = 1, +}; + +enum batadv_dhcpoptioncode { + BATADV_DHCP_OPT_PAD = 0, + BATADV_DHCP_OPT_MSG_TYPE = 53, + BATADV_DHCP_OPT_END = 255, +}; + +enum batadv_dhcptype { + BATADV_DHCPACK = 5, +}; + +/* { 99, 130, 83, 99 } */ +#define BATADV_DHCP_MAGIC 1669485411 + +struct batadv_dhcp_packet { + __u8 op; + __u8 htype; + __u8 hlen; + __u8 hops; + __be32 xid; + __be16 secs; + __be16 flags; + __be32 ciaddr; + __be32 yiaddr; + __be32 siaddr; + __be32 giaddr; + __u8 chaddr[16]; + __u8 sname[64]; + __u8 file[128]; + __be32 magic; + __u8 options[0]; +}; + +#define BATADV_DHCP_YIADDR_LEN sizeof(((struct batadv_dhcp_packet *)0)->yiaddr) +#define BATADV_DHCP_CHADDR_LEN sizeof(((struct batadv_dhcp_packet *)0)->chaddr) + static void batadv_dat_purge(struct work_struct *work); /** @@ -1440,6 +1486,359 @@ out: } /** + * batadv_dat_check_dhcp_ipudp() - check skb for IP+UDP headers valid for DHCP + * @skb: the packet to check + * @ip_src: a buffer to store the IPv4 source address in + * + * Checks whether the given skb has an IP and UDP header valid for a DHCP + * message from a DHCP server. And if so, stores the IPv4 source address in + * the provided buffer. + * + * Return: True if valid, false otherwise. + */ +static bool +batadv_dat_check_dhcp_ipudp(struct sk_buff *skb, __be32 *ip_src) +{ + unsigned int offset = skb_network_offset(skb); + struct udphdr *udphdr, _udphdr; + struct iphdr *iphdr, _iphdr; + + iphdr = skb_header_pointer(skb, offset, sizeof(_iphdr), &_iphdr); + if (!iphdr || iphdr->version != 4 || iphdr->ihl * 4 < sizeof(_iphdr)) + return false; + + if (iphdr->protocol != IPPROTO_UDP) + return false; + + offset += iphdr->ihl * 4; + skb_set_transport_header(skb, offset); + + udphdr = skb_header_pointer(skb, offset, sizeof(_udphdr), &_udphdr); + if (!udphdr || udphdr->source != htons(67)) + return false; + + *ip_src = get_unaligned(&iphdr->saddr); + + return true; +} + +/** + * batadv_dat_check_dhcp() - examine packet for valid DHCP message + * @skb: the packet to check + * @proto: ethernet protocol hint (behind a potential vlan) + * @ip_src: a buffer to store the IPv4 source address in + * + * Checks whether the given skb is a valid DHCP packet. And if so, stores the + * IPv4 source address in the provided buffer. + * + * Caller needs to ensure that the skb network header is set correctly. + * + * Return: If skb is a valid DHCP packet, then returns its op code + * (e.g. BOOTREPLY vs. BOOTREQUEST). Otherwise returns -EINVAL. + */ +static int +batadv_dat_check_dhcp(struct sk_buff *skb, __be16 proto, __be32 *ip_src) +{ + __be32 *magic, _magic; + unsigned int offset; + struct { + __u8 op; + __u8 htype; + __u8 hlen; + __u8 hops; + } *dhcp_h, _dhcp_h; + + if (proto != htons(ETH_P_IP)) + return -EINVAL; + + if (!batadv_dat_check_dhcp_ipudp(skb, ip_src)) + return -EINVAL; + + offset = skb_transport_offset(skb) + sizeof(struct udphdr); + if (skb->len < offset + sizeof(struct batadv_dhcp_packet)) + return -EINVAL; + + dhcp_h = skb_header_pointer(skb, offset, sizeof(_dhcp_h), &_dhcp_h); + if (!dhcp_h || dhcp_h->htype != BATADV_HTYPE_ETHERNET || + dhcp_h->hlen != ETH_ALEN) + return -EINVAL; + + offset += offsetof(struct batadv_dhcp_packet, magic); + + magic = skb_header_pointer(skb, offset, sizeof(_magic), &_magic); + if (!magic || get_unaligned(magic) != htonl(BATADV_DHCP_MAGIC)) + return -EINVAL; + + return dhcp_h->op; +} + +/** + * batadv_dat_get_dhcp_message_type() - get message type of a DHCP packet + * @skb: the DHCP packet to parse + * + * Iterates over the DHCP options of the given DHCP packet to find a + * DHCP Message Type option and parse it. + * + * Caller needs to ensure that the given skb is a valid DHCP packet and + * that the skb transport header is set correctly. + * + * Return: The found DHCP message type value, if found. -EINVAL otherwise. + */ +static int batadv_dat_get_dhcp_message_type(struct sk_buff *skb) +{ + unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr); + u8 *type, _type; + struct { + u8 type; + u8 len; + } *tl, _tl; + + offset += sizeof(struct batadv_dhcp_packet); + + while ((tl = skb_header_pointer(skb, offset, sizeof(_tl), &_tl))) { + if (tl->type == BATADV_DHCP_OPT_MSG_TYPE) + break; + + if (tl->type == BATADV_DHCP_OPT_END) + break; + + if (tl->type == BATADV_DHCP_OPT_PAD) + offset++; + else + offset += tl->len + sizeof(_tl); + } + + /* Option Overload Code not supported */ + if (!tl || tl->type != BATADV_DHCP_OPT_MSG_TYPE || + tl->len != sizeof(_type)) + return -EINVAL; + + offset += sizeof(_tl); + + type = skb_header_pointer(skb, offset, sizeof(_type), &_type); + if (!type) + return -EINVAL; + + return *type; +} + +/** + * batadv_dat_get_dhcp_yiaddr() - get yiaddr from a DHCP packet + * @skb: the DHCP packet to parse + * @buf: a buffer to store the yiaddr in + * + * Caller needs to ensure that the given skb is a valid DHCP packet and + * that the skb transport header is set correctly. + * + * Return: True on success, false otherwise. + */ +static bool batadv_dat_dhcp_get_yiaddr(struct sk_buff *skb, __be32 *buf) +{ + unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr); + __be32 *yiaddr; + + offset += offsetof(struct batadv_dhcp_packet, yiaddr); + yiaddr = skb_header_pointer(skb, offset, BATADV_DHCP_YIADDR_LEN, buf); + + if (!yiaddr) + return false; + + if (yiaddr != buf) + *buf = get_unaligned(yiaddr); + + return true; +} + +/** + * batadv_dat_get_dhcp_chaddr() - get chaddr from a DHCP packet + * @skb: the DHCP packet to parse + * @buf: a buffer to store the chaddr in + * + * Caller needs to ensure that the given skb is a valid DHCP packet and + * that the skb transport header is set correctly. + * + * Return: True on success, false otherwise + */ +static bool batadv_dat_get_dhcp_chaddr(struct sk_buff *skb, u8 *buf) +{ + unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr); + u8 *chaddr; + + offset += offsetof(struct batadv_dhcp_packet, chaddr); + chaddr = skb_header_pointer(skb, offset, BATADV_DHCP_CHADDR_LEN, buf); + + if (!chaddr) + return false; + + if (chaddr != buf) + memcpy(buf, chaddr, BATADV_DHCP_CHADDR_LEN); + + return true; +} + +/** + * batadv_dat_put_dhcp() - puts addresses from a DHCP packet into the DHT and + * DAT cache + * @bat_priv: the bat priv with all the soft interface information + * @chaddr: the DHCP client MAC address + * @yiaddr: the DHCP client IP address + * @hw_dst: the DHCP server MAC address + * @ip_dst: the DHCP server IP address + * @vid: VLAN identifier + * + * Adds given MAC/IP pairs to the local DAT cache and propagates them further + * into the DHT. + * + * For the DHT propagation, client MAC + IP will appear as the ARP Reply + * transmitter (and hw_dst/ip_dst as the target). + */ +static void batadv_dat_put_dhcp(struct batadv_priv *bat_priv, u8 *chaddr, + __be32 yiaddr, u8 *hw_dst, __be32 ip_dst, + unsigned short vid) +{ + struct sk_buff *skb; + + skb = batadv_dat_arp_create_reply(bat_priv, yiaddr, ip_dst, chaddr, + hw_dst, vid); + if (!skb) + return; + + skb_set_network_header(skb, ETH_HLEN); + + batadv_dat_entry_add(bat_priv, yiaddr, chaddr, vid); + batadv_dat_entry_add(bat_priv, ip_dst, hw_dst, vid); + + batadv_dat_send_data(bat_priv, skb, yiaddr, vid, BATADV_P_DAT_DHT_PUT); + batadv_dat_send_data(bat_priv, skb, ip_dst, vid, BATADV_P_DAT_DHT_PUT); + + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "Snooped from outgoing DHCPACK (server address): %pI4, %pM (vid: %i)\n", + &ip_dst, hw_dst, batadv_print_vid(vid)); + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "Snooped from outgoing DHCPACK (client address): %pI4, %pM (vid: %i)\n", + &yiaddr, chaddr, batadv_print_vid(vid)); +} + +/** + * batadv_dat_check_dhcp_ack() - examine packet for valid DHCP message + * @skb: the packet to check + * @proto: ethernet protocol hint (behind a potential vlan) + * @ip_src: a buffer to store the IPv4 source address in + * @chaddr: a buffer to store the DHCP Client Hardware Address in + * @yiaddr: a buffer to store the DHCP Your IP Address in + * + * Checks whether the given skb is a valid DHCPACK. And if so, stores the + * IPv4 server source address (ip_src), client MAC address (chaddr) and client + * IPv4 address (yiaddr) in the provided buffers. + * + * Caller needs to ensure that the skb network header is set correctly. + * + * Return: True if the skb is a valid DHCPACK. False otherwise. + */ +static bool +batadv_dat_check_dhcp_ack(struct sk_buff *skb, __be16 proto, __be32 *ip_src, + u8 *chaddr, __be32 *yiaddr) +{ + int type; + + type = batadv_dat_check_dhcp(skb, proto, ip_src); + if (type != BATADV_BOOTREPLY) + return false; + + type = batadv_dat_get_dhcp_message_type(skb); + if (type != BATADV_DHCPACK) + return false; + + if (!batadv_dat_dhcp_get_yiaddr(skb, yiaddr)) + return false; + + if (!batadv_dat_get_dhcp_chaddr(skb, chaddr)) + return false; + + return true; +} + +/** + * batadv_dat_snoop_outgoing_dhcp_ack() - snoop DHCPACK and fill DAT with it + * @bat_priv: the bat priv with all the soft interface information + * @skb: the packet to snoop + * @proto: ethernet protocol hint (behind a potential vlan) + * @vid: VLAN identifier + * + * This function first checks whether the given skb is a valid DHCPACK. If + * so then its source MAC and IP as well as its DHCP Client Hardware Address + * field and DHCP Your IP Address field are added to the local DAT cache and + * propagated into the DHT. + * + * Caller needs to ensure that the skb mac and network headers are set + * correctly. + */ +void batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv, + struct sk_buff *skb, + __be16 proto, + unsigned short vid) +{ + u8 chaddr[BATADV_DHCP_CHADDR_LEN]; + __be32 ip_src, yiaddr; + + if (!atomic_read(&bat_priv->distributed_arp_table)) + return; + + if (!batadv_dat_check_dhcp_ack(skb, proto, &ip_src, chaddr, &yiaddr)) + return; + + batadv_dat_put_dhcp(bat_priv, chaddr, yiaddr, eth_hdr(skb)->h_source, + ip_src, vid); +} + +/** + * batadv_dat_snoop_incoming_dhcp_ack() - snoop DHCPACK and fill DAT cache + * @bat_priv: the bat priv with all the soft interface information + * @skb: the packet to snoop + * @hdr_size: header size, up to the tail of the batman-adv header + * + * This function first checks whether the given skb is a valid DHCPACK. If + * so then its source MAC and IP as well as its DHCP Client Hardware Address + * field and DHCP Your IP Address field are added to the local DAT cache. + */ +void batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ + u8 chaddr[BATADV_DHCP_CHADDR_LEN]; + struct ethhdr *ethhdr; + __be32 ip_src, yiaddr; + unsigned short vid; + __be16 proto; + u8 *hw_src; + + if (!atomic_read(&bat_priv->distributed_arp_table)) + return; + + if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN))) + return; + + ethhdr = (struct ethhdr *)(skb->data + hdr_size); + skb_set_network_header(skb, hdr_size + ETH_HLEN); + proto = ethhdr->h_proto; + + if (!batadv_dat_check_dhcp_ack(skb, proto, &ip_src, chaddr, &yiaddr)) + return; + + hw_src = ethhdr->h_source; + vid = batadv_dat_get_vid(skb, &hdr_size); + + batadv_dat_entry_add(bat_priv, yiaddr, chaddr, vid); + batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); + + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "Snooped from incoming DHCPACK (server address): %pI4, %pM (vid: %i)\n", + &ip_src, hw_src, batadv_print_vid(vid)); + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "Snooped from incoming DHCPACK (client address): %pI4, %pM (vid: %i)\n", + &yiaddr, chaddr, batadv_print_vid(vid)); +} + +/** * batadv_dat_drop_broadcast_packet() - check if an ARP request has to be * dropped (because the node has already obtained the reply via DAT) or not * @bat_priv: the bat priv with all the soft interface information diff --git a/net/batman-adv/distributed-arp-table.h b/net/batman-adv/distributed-arp-table.h index a04596028337..e58d7a9bfc8d 100644 --- a/net/batman-adv/distributed-arp-table.h +++ b/net/batman-adv/distributed-arp-table.h @@ -46,6 +46,12 @@ void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv, struct sk_buff *skb); bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, struct sk_buff *skb, int hdr_size); +void batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv, + struct sk_buff *skb, + __be16 proto, + unsigned short vid); +void batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_size); bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv, struct batadv_forw_packet *forw_packet); @@ -140,6 +146,19 @@ batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, return false; } +static inline void +batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv, + struct sk_buff *skb, __be16 proto, + unsigned short vid) +{ +} + +static inline void +batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ +} + static inline bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv, struct batadv_forw_packet *forw_packet) diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index cc3ed93a6d51..469fa97d1add 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -1043,6 +1043,8 @@ int batadv_recv_unicast_packet(struct sk_buff *skb, hdr_size)) goto rx_success; + batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size); + batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node); @@ -1278,6 +1280,8 @@ int batadv_recv_bcast_packet(struct sk_buff *skb, if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size)) goto rx_success; + batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size); + /* broadcast for me */ batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node); diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 5db5a0a4c959..943071008670 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -212,6 +212,7 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, enum batadv_forw_mode forw_mode; struct batadv_orig_node *mcast_single_orig = NULL; int network_offset = ETH_HLEN; + __be16 proto; if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE) goto dropped; @@ -223,12 +224,15 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, vid = batadv_get_vid(skb, 0); ethhdr = eth_hdr(skb); - switch (ntohs(ethhdr->h_proto)) { + proto = ethhdr->h_proto; + + switch (ntohs(proto)) { case ETH_P_8021Q: vhdr = vlan_eth_hdr(skb); + proto = vhdr->h_vlan_encapsulated_proto; /* drop batman-in-batman packets to prevent loops */ - if (vhdr->h_vlan_encapsulated_proto != htons(ETH_P_BATMAN)) { + if (proto != htons(ETH_P_BATMAN)) { network_offset += VLAN_HLEN; break; } @@ -256,6 +260,9 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, goto dropped; } + /* Snoop address candidates from DHCPACKs for early DAT filling */ + batadv_dat_snoop_outgoing_dhcp_ack(bat_priv, skb, proto, vid); + /* don't accept stp packets. STP does not help in meshes. * better use the bridge loop avoidance ... * |