diff options
Diffstat (limited to 'net/ax25/ax25_ip.c')
| -rw-r--r-- | net/ax25/ax25_ip.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/net/ax25/ax25_ip.c b/net/ax25/ax25_ip.c new file mode 100644 index 000000000..e4f63dd43 --- /dev/null +++ b/net/ax25/ax25_ip.c @@ -0,0 +1,248 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * + * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) + */ +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/in.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/slab.h> +#include <net/ax25.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/if_arp.h> +#include <linux/skbuff.h> +#include <net/sock.h> +#include <linux/uaccess.h> +#include <linux/fcntl.h> +#include <linux/termios.h> /* For TIOCINQ/OUTQ */ +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/notifier.h> +#include <linux/proc_fs.h> +#include <linux/stat.h> +#include <linux/sysctl.h> +#include <net/ip.h> +#include <net/arp.h> + +/* + * IP over AX.25 encapsulation. + */ + +/* + * Shove an AX.25 UI header on an IP packet and handle ARP + */ + +#ifdef CONFIG_INET + +static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, + unsigned short type, const void *daddr, + const void *saddr, unsigned int len) +{ + unsigned char *buff; + + /* they sometimes come back to us... */ + if (type == ETH_P_AX25) + return 0; + + /* header is an AX.25 UI frame from us to them */ + buff = skb_push(skb, AX25_HEADER_LEN); + *buff++ = 0x00; /* KISS DATA */ + + if (daddr != NULL) + memcpy(buff, daddr, dev->addr_len); /* Address specified */ + + buff[6] &= ~AX25_CBIT; + buff[6] &= ~AX25_EBIT; + buff[6] |= AX25_SSSID_SPARE; + buff += AX25_ADDR_LEN; + + if (saddr != NULL) + memcpy(buff, saddr, dev->addr_len); + else + memcpy(buff, dev->dev_addr, dev->addr_len); + + buff[6] &= ~AX25_CBIT; + buff[6] |= AX25_EBIT; + buff[6] |= AX25_SSSID_SPARE; + buff += AX25_ADDR_LEN; + + *buff++ = AX25_UI; /* UI */ + + /* Append a suitable AX.25 PID */ + switch (type) { + case ETH_P_IP: + *buff++ = AX25_P_IP; + break; + case ETH_P_ARP: + *buff++ = AX25_P_ARP; + break; + default: + printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type); + *buff++ = 0; + break; + } + + if (daddr != NULL) + return AX25_HEADER_LEN; + + return -AX25_HEADER_LEN; /* Unfinished header */ +} + +netdev_tx_t ax25_ip_xmit(struct sk_buff *skb) +{ + struct sk_buff *ourskb; + unsigned char *bp = skb->data; + ax25_route *route; + struct net_device *dev = NULL; + ax25_address *src, *dst; + ax25_digi *digipeat = NULL; + ax25_dev *ax25_dev; + ax25_cb *ax25; + char ip_mode = ' '; + + dst = (ax25_address *)(bp + 1); + src = (ax25_address *)(bp + 8); + + ax25_route_lock_use(); + route = ax25_get_route(dst, NULL); + if (route) { + digipeat = route->digipeat; + dev = route->dev; + ip_mode = route->ip_mode; + } + + if (dev == NULL) + dev = skb->dev; + + if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { + kfree_skb(skb); + goto put; + } + + if (bp[16] == AX25_P_IP) { + if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) { + /* + * We copy the buffer and release the original thereby + * keeping it straight + * + * Note: we report 1 back so the caller will + * not feed the frame direct to the physical device + * We don't want that to happen. (It won't be upset + * as we have pulled the frame from the queue by + * freeing it). + * + * NB: TCP modifies buffers that are still + * on a device queue, thus we use skb_copy() + * instead of using skb_clone() unless this + * gets fixed. + */ + + ax25_address src_c; + ax25_address dst_c; + + if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) { + kfree_skb(skb); + goto put; + } + + if (skb->sk != NULL) + skb_set_owner_w(ourskb, skb->sk); + + kfree_skb(skb); + /* dl9sau: bugfix + * after kfree_skb(), dst and src which were pointer + * to bp which is part of skb->data would not be valid + * anymore hope that after skb_pull(ourskb, ..) our + * dsc_c and src_c will not become invalid + */ + bp = ourskb->data; + dst_c = *(ax25_address *)(bp + 1); + src_c = *(ax25_address *)(bp + 8); + + skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */ + skb_reset_network_header(ourskb); + + ax25=ax25_send_frame( + ourskb, + ax25_dev->values[AX25_VALUES_PACLEN], + &src_c, + &dst_c, digipeat, dev); + if (ax25) { + ax25_cb_put(ax25); + } + goto put; + } + } + + bp[7] &= ~AX25_CBIT; + bp[7] &= ~AX25_EBIT; + bp[7] |= AX25_SSSID_SPARE; + + bp[14] &= ~AX25_CBIT; + bp[14] |= AX25_EBIT; + bp[14] |= AX25_SSSID_SPARE; + + skb_pull(skb, AX25_KISS_HEADER_LEN); + + if (digipeat != NULL) { + if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) { + kfree_skb(skb); + goto put; + } + + skb = ourskb; + } + + ax25_queue_xmit(skb, dev); + +put: + + ax25_route_lock_unuse(); + return NETDEV_TX_OK; +} + +#else /* INET */ + +static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, + unsigned short type, const void *daddr, + const void *saddr, unsigned int len) +{ + return -AX25_HEADER_LEN; +} + +netdev_tx_t ax25_ip_xmit(struct sk_buff *skb) +{ + kfree_skb(skb); + return NETDEV_TX_OK; +} +#endif + +static bool ax25_validate_header(const char *header, unsigned int len) +{ + ax25_digi digi; + + if (!len) + return false; + + if (header[0]) + return true; + + return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL, + NULL); +} + +const struct header_ops ax25_header_ops = { + .create = ax25_hard_header, + .validate = ax25_validate_header, +}; + +EXPORT_SYMBOL(ax25_header_ops); +EXPORT_SYMBOL(ax25_ip_xmit); |