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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ax25/ax25_in.c | |
download | op-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip op-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'net/ax25/ax25_in.c')
-rw-r--r-- | net/ax25/ax25_in.c | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/net/ax25/ax25_in.c b/net/ax25/ax25_in.c new file mode 100644 index 0000000..3dc808f --- /dev/null +++ b/net/ax25/ax25_in.c @@ -0,0 +1,470 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk) + * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) + * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) + * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de) + */ +#include <linux/config.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/in.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <net/ax25.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/netfilter.h> +#include <net/sock.h> +#include <net/ip.h> /* For ip_rcv */ +#include <net/tcp.h> +#include <net/arp.h> /* For arp_rcv */ +#include <asm/uaccess.h> +#include <asm/system.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> + +/* + * Given a fragment, queue it on the fragment queue and if the fragment + * is complete, send it back to ax25_rx_iframe. + */ +static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb) +{ + struct sk_buff *skbn, *skbo; + + if (ax25->fragno != 0) { + if (!(*skb->data & AX25_SEG_FIRST)) { + if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) { + /* Enqueue fragment */ + ax25->fragno = *skb->data & AX25_SEG_REM; + skb_pull(skb, 1); /* skip fragno */ + ax25->fraglen += skb->len; + skb_queue_tail(&ax25->frag_queue, skb); + + /* Last fragment received ? */ + if (ax25->fragno == 0) { + skbn = alloc_skb(AX25_MAX_HEADER_LEN + + ax25->fraglen, + GFP_ATOMIC); + if (!skbn) { + skb_queue_purge(&ax25->frag_queue); + return 1; + } + + skb_reserve(skbn, AX25_MAX_HEADER_LEN); + + skbn->dev = ax25->ax25_dev->dev; + skbn->h.raw = skbn->data; + skbn->nh.raw = skbn->data; + + /* Copy data from the fragments */ + while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) { + memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len); + kfree_skb(skbo); + } + + ax25->fraglen = 0; + + if (ax25_rx_iframe(ax25, skbn) == 0) + kfree_skb(skbn); + } + + return 1; + } + } + } else { + /* First fragment received */ + if (*skb->data & AX25_SEG_FIRST) { + skb_queue_purge(&ax25->frag_queue); + ax25->fragno = *skb->data & AX25_SEG_REM; + skb_pull(skb, 1); /* skip fragno */ + ax25->fraglen = skb->len; + skb_queue_tail(&ax25->frag_queue, skb); + return 1; + } + } + + return 0; +} + +/* + * This is where all valid I frames are sent to, to be dispatched to + * whichever protocol requires them. + */ +int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb) +{ + int (*func)(struct sk_buff *, ax25_cb *); + volatile int queued = 0; + unsigned char pid; + + if (skb == NULL) return 0; + + ax25_start_idletimer(ax25); + + pid = *skb->data; + +#ifdef CONFIG_INET + if (pid == AX25_P_IP) { + /* working around a TCP bug to keep additional listeners + * happy. TCP re-uses the buffer and destroys the original + * content. + */ + struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC); + if (skbn != NULL) { + kfree_skb(skb); + skb = skbn; + } + + skb_pull(skb, 1); /* Remove PID */ + skb->h.raw = skb->data; + skb->nh.raw = skb->data; + skb->dev = ax25->ax25_dev->dev; + skb->pkt_type = PACKET_HOST; + skb->protocol = htons(ETH_P_IP); + ip_rcv(skb, skb->dev, NULL); /* Wrong ptype */ + return 1; + } +#endif + if (pid == AX25_P_SEGMENT) { + skb_pull(skb, 1); /* Remove PID */ + return ax25_rx_fragment(ax25, skb); + } + + if ((func = ax25_protocol_function(pid)) != NULL) { + skb_pull(skb, 1); /* Remove PID */ + return (*func)(skb, ax25); + } + + if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) { + if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) || + ax25->pidincl) { + if (sock_queue_rcv_skb(ax25->sk, skb) == 0) + queued = 1; + else + ax25->condition |= AX25_COND_OWN_RX_BUSY; + } + } + + return queued; +} + +/* + * Higher level upcall for a LAPB frame + */ +static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama) +{ + int queued = 0; + + if (ax25->state == AX25_STATE_0) + return 0; + + switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { + case AX25_PROTO_STD_SIMPLEX: + case AX25_PROTO_STD_DUPLEX: + queued = ax25_std_frame_in(ax25, skb, type); + break; + +#ifdef CONFIG_AX25_DAMA_SLAVE + case AX25_PROTO_DAMA_SLAVE: + if (dama || ax25->ax25_dev->dama.slave) + queued = ax25_ds_frame_in(ax25, skb, type); + else + queued = ax25_std_frame_in(ax25, skb, type); + break; +#endif + } + + return queued; +} + +static int ax25_rcv(struct sk_buff *skb, struct net_device *dev, + ax25_address *dev_addr, struct packet_type *ptype) +{ + ax25_address src, dest, *next_digi = NULL; + int type = 0, mine = 0, dama; + struct sock *make, *sk; + ax25_digi dp, reverse_dp; + ax25_cb *ax25; + ax25_dev *ax25_dev; + + /* + * Process the AX.25/LAPB frame. + */ + + skb->h.raw = skb->data; + + if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { + kfree_skb(skb); + return 0; + } + + /* + * Parse the address header. + */ + + if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) { + kfree_skb(skb); + return 0; + } + + /* + * Ours perhaps ? + */ + if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */ + next_digi = &dp.calls[dp.lastrepeat + 1]; + + /* + * Pull of the AX.25 headers leaving the CTRL/PID bytes + */ + skb_pull(skb, ax25_addr_size(&dp)); + + /* For our port addresses ? */ + if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi) + mine = 1; + + /* Also match on any registered callsign from L3/4 */ + if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi) + mine = 1; + + /* UI frame - bypass LAPB processing */ + if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) { + skb->h.raw = skb->data + 2; /* skip control and pid */ + + ax25_send_to_raw(&dest, skb, skb->data[1]); + + if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) { + kfree_skb(skb); + return 0; + } + + /* Now we are pointing at the pid byte */ + switch (skb->data[1]) { +#ifdef CONFIG_INET + case AX25_P_IP: + skb_pull(skb,2); /* drop PID/CTRL */ + skb->h.raw = skb->data; + skb->nh.raw = skb->data; + skb->dev = dev; + skb->pkt_type = PACKET_HOST; + skb->protocol = htons(ETH_P_IP); + ip_rcv(skb, dev, ptype); /* Note ptype here is the wrong one, fix me later */ + break; + + case AX25_P_ARP: + skb_pull(skb,2); + skb->h.raw = skb->data; + skb->nh.raw = skb->data; + skb->dev = dev; + skb->pkt_type = PACKET_HOST; + skb->protocol = htons(ETH_P_ARP); + arp_rcv(skb, dev, ptype); /* Note ptype here is wrong... */ + break; +#endif + case AX25_P_TEXT: + /* Now find a suitable dgram socket */ + sk = ax25_get_socket(&dest, &src, SOCK_DGRAM); + if (sk != NULL) { + bh_lock_sock(sk); + if (atomic_read(&sk->sk_rmem_alloc) >= + sk->sk_rcvbuf) { + kfree_skb(skb); + } else { + /* + * Remove the control and PID. + */ + skb_pull(skb, 2); + if (sock_queue_rcv_skb(sk, skb) != 0) + kfree_skb(skb); + } + bh_unlock_sock(sk); + sock_put(sk); + } else { + kfree_skb(skb); + } + break; + + default: + kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */ + break; + } + + return 0; + } + + /* + * Is connected mode supported on this device ? + * If not, should we DM the incoming frame (except DMs) or + * silently ignore them. For now we stay quiet. + */ + if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) { + kfree_skb(skb); + return 0; + } + + /* LAPB */ + + /* AX.25 state 1-4 */ + + ax25_digi_invert(&dp, &reverse_dp); + + if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) { + /* + * Process the frame. If it is queued up internally it + * returns one otherwise we free it immediately. This + * routine itself wakes the user context layers so we do + * no further work + */ + if (ax25_process_rx_frame(ax25, skb, type, dama) == 0) + kfree_skb(skb); + + ax25_cb_put(ax25); + return 0; + } + + /* AX.25 state 0 (disconnected) */ + + /* a) received not a SABM(E) */ + + if ((*skb->data & ~AX25_PF) != AX25_SABM && + (*skb->data & ~AX25_PF) != AX25_SABME) { + /* + * Never reply to a DM. Also ignore any connects for + * addresses that are not our interfaces and not a socket. + */ + if ((*skb->data & ~AX25_PF) != AX25_DM && mine) + ax25_return_dm(dev, &src, &dest, &dp); + + kfree_skb(skb); + return 0; + } + + /* b) received SABM(E) */ + + if (dp.lastrepeat + 1 == dp.ndigi) + sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET); + else + sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET); + + if (sk != NULL) { + bh_lock_sock(sk); + if (sk_acceptq_is_full(sk) || + (make = ax25_make_new(sk, ax25_dev)) == NULL) { + if (mine) + ax25_return_dm(dev, &src, &dest, &dp); + kfree_skb(skb); + bh_unlock_sock(sk); + sock_put(sk); + + return 0; + } + + ax25 = ax25_sk(make); + skb_set_owner_r(skb, make); + skb_queue_head(&sk->sk_receive_queue, skb); + + make->sk_state = TCP_ESTABLISHED; + + sk->sk_ack_backlog++; + bh_unlock_sock(sk); + } else { + if (!mine) { + kfree_skb(skb); + return 0; + } + + if ((ax25 = ax25_create_cb()) == NULL) { + ax25_return_dm(dev, &src, &dest, &dp); + kfree_skb(skb); + return 0; + } + + ax25_fillin_cb(ax25, ax25_dev); + } + + ax25->source_addr = dest; + ax25->dest_addr = src; + + /* + * Sort out any digipeated paths. + */ + if (dp.ndigi && !ax25->digipeat && + (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) { + kfree_skb(skb); + ax25_destroy_socket(ax25); + if (sk) + sock_put(sk); + return 0; + } + + if (dp.ndigi == 0) { + if (ax25->digipeat != NULL) { + kfree(ax25->digipeat); + ax25->digipeat = NULL; + } + } else { + /* Reverse the source SABM's path */ + memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi)); + } + + if ((*skb->data & ~AX25_PF) == AX25_SABME) { + ax25->modulus = AX25_EMODULUS; + ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW]; + } else { + ax25->modulus = AX25_MODULUS; + ax25->window = ax25_dev->values[AX25_VALUES_WINDOW]; + } + + ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE); + +#ifdef CONFIG_AX25_DAMA_SLAVE + if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE) + ax25_dama_on(ax25); +#endif + + ax25->state = AX25_STATE_3; + + ax25_cb_add(ax25); + + ax25_start_heartbeat(ax25); + ax25_start_t3timer(ax25); + ax25_start_idletimer(ax25); + + if (sk) { + if (!sock_flag(sk, SOCK_DEAD)) + sk->sk_data_ready(sk, skb->len); + sock_put(sk); + } else + kfree_skb(skb); + + return 0; +} + +/* + * Receive an AX.25 frame via a SLIP interface. + */ +int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev, + struct packet_type *ptype) +{ + skb->sk = NULL; /* Initially we don't know who it's for */ + skb->destructor = NULL; /* Who initializes this, dammit?! */ + + if ((*skb->data & 0x0F) != 0) { + kfree_skb(skb); /* Not a KISS data frame */ + return 0; + } + + skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */ + + return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype); +} |