This patch allows one to use the SO_BINDTODEVICE and a new ioctl against
net_device objects to send and receive regular routed traffic between two
interfaces on the same machine. It also fixes a problem when using BINDTODEVICE:
the old code does not set the bound_if correctly when sending back the
syn-ack during TCP connection initialization.
I'm not sure how useful others will find it, but it amuses me ;)
Comments and suggestions welcome.
Thanks,
Ben
-- Ben Greear <greearb@candelatech.com> <Ben_Greear AT excite.com> President of Candela Technologies Inc http://www.candelatech.com ScryMUD: http://scry.wanfear.com http://scry.wanfear.com/~greear
--------------010703030901020509080500 Content-Type: text/plain; name="sts_2.4.19.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="sts_2.4.19.patch"
--- linux-2.4.19/include/linux/sockios.h Wed Nov 7 15:39:36 2001 +++ linux-2.4.19.dev/include/linux/sockios.h Sun Sep 15 21:10:00 2002 @@ -114,6 +114,16 @@ #define SIOCBONDINFOQUERY 0x8994 /* rtn info about bond state */ #define SIOCBONDCHANGEACTIVE 0x8995 /* update to a new active slave */ + +/* Ben's little hack land */ +#define SIOCSACCEPTLOCALADDRS 0x89a0 /* Allow interfaces to accept pkts from + * local interfaces...use with SO_BINDTODEVICE + */ +#define SIOCGACCEPTLOCALADDRS 0x89a1 /* Allow interfaces to accept pkts from + * local interfaces...use with SO_BINDTODEVICE + */ + + /* Device private ioctl calls */ /* --- linux-2.4.19/net/Config.in Fri Aug 2 17:39:46 2002 +++ linux-2.4.19.dev/net/Config.in Sun Sep 15 21:27:08 2002 @@ -97,6 +97,7 @@ mainmenu_option next_comment comment 'Network testing' tristate 'Packet Generator (USE WITH CAUTION)' CONFIG_NET_PKTGEN +bool 'Send-to-Self' CONFIG_NET_SENDTOSELF endmenu endmenu --- linux-2.4.19/include/net/tcp.h Fri Aug 2 17:39:46 2002 +++ linux-2.4.19.dev/include/net/tcp.h Sun Sep 15 21:57:07 2002 @@ -27,6 +27,7 @@ #include <linux/config.h> #include <linux/tcp.h> #include <linux/slab.h> +#include <linux/cache.h> #include <net/checksum.h> #include <net/sock.h> @@ -117,8 +118,7 @@ * Now align to a new cache line as all the following members * are often dirty. */ - rwlock_t __tcp_lhash_lock - __attribute__((__aligned__(SMP_CACHE_BYTES))); + rwlock_t __tcp_lhash_lock ____cacheline_aligned; atomic_t __tcp_lhash_users; wait_queue_head_t __tcp_lhash_wait; spinlock_t __tcp_portalloc_lock; @@ -447,7 +447,6 @@ extern int sysctl_tcp_retrans_collapse; extern int sysctl_tcp_stdurg; extern int sysctl_tcp_rfc1337; -extern int sysctl_tcp_tw_recycle; extern int sysctl_tcp_abort_on_overflow; extern int sysctl_tcp_max_orphans; extern int sysctl_tcp_max_tw_buckets; @@ -520,6 +519,14 @@ struct tcp_v6_open_req v6_req; #endif } af; +#ifdef CONFIG_NET_SENDTOSELF + int bound_dev_if; /* This is so we can connect to ourselves and not collide + * in the open-request hash (the addresses and ports are the + * same, but we need two ends, so use the interface to determine + * one from the other. Active when SO_BINDTODEVICE is used. + * --Ben + */ +#endif }; /* SLAB cache for open requests. */ --- linux-2.4.19/net/ipv4/arp.c Fri Aug 2 17:39:46 2002 +++ linux-2.4.19.dev/net/ipv4/arp.c Sun Sep 15 21:14:43 2002 @@ -1,4 +1,4 @@ -/* linux/net/inet/arp.c +/* linux/net/inet/arp.c -*-linux-c-*- * * Version: $Id: sts_2.4.19.patch,v 1.3 2002/09/17 07:01:55 greear Exp $ * @@ -351,12 +351,26 @@ int flag = 0; /*unsigned long now; */ - if (ip_route_output(&rt, sip, tip, 0, 0) < 0) + if (ip_route_output(&rt, sip, tip, 0, 0) < 0) return 1; - if (rt->u.dst.dev != dev) { - NET_INC_STATS_BH(ArpFilter); - flag = 1; - } + + if (rt->u.dst.dev != dev) { +#ifdef CONFIG_NET_SENDTOSELF + if ((dev->priv_flags & IFF_ACCEPT_LOCAL_ADDRS) && + (rt->u.dst.dev == &loopback_dev)) { + /* OK, we'll let this special case slide, so that we can arp from one + * local interface to another. This seems to work, but could use some + * review. --Ben + */ + } + else { +#endif + NET_INC_STATS_BH(ArpFilter); + flag = 1; +#ifdef CONFIG_NET_SENDTOSELF + } +#endif + } ip_rt_put(rt); return flag; } --- linux-2.4.19/net/ipv4/fib_frontend.c Fri Aug 2 17:39:46 2002 +++ linux-2.4.19.dev/net/ipv4/fib_frontend.c Sun Sep 15 21:16:44 2002 @@ -233,8 +233,19 @@ if (fib_lookup(&key, &res)) goto last_resort; - if (res.type != RTN_UNICAST) - goto e_inval_res; + + if (res.type != RTN_UNICAST) { +#ifdef CONFIG_NET_SENDTOSELF + if ((res.type == RTN_LOCAL) && + (dev->priv_flags & IFF_ACCEPT_LOCAL_ADDRS)) { + /* All is OK */ + } + else +#endif + goto e_inval_res; + + } + *spec_dst = FIB_RES_PREFSRC(res); fib_combine_itag(itag, &res); #ifdef CONFIG_IP_ROUTE_MULTIPATH --- linux-2.4.19/net/ipv4/ip_output.c Fri Aug 2 17:39:46 2002 +++ linux-2.4.19.dev/net/ipv4/ip_output.c Sun Sep 15 21:19:45 2002 @@ -520,8 +520,18 @@ /* * Get the memory we require with some space left for alignment. */ - - skb = sock_alloc_send_skb(sk, fraglen+hh_len+15, flags&MSG_DONTWAIT, &err); + if (!(flags & MSG_DONTWAIT) || nfrags == 0) { + skb = sock_alloc_send_skb(sk, fraglen + hh_len + 15, + (flags & MSG_DONTWAIT), &err); + } else { + /* On a non-blocking write, we check for send buffer + * usage on the first fragment only. + */ + skb = sock_wmalloc(sk, fraglen + hh_len + 15, 1, + sk->allocation); + if (!skb) + err = -ENOBUFS; + } if (skb == NULL) goto error; @@ -965,7 +975,11 @@ daddr = replyopts.opt.faddr; } +#ifdef CONFIG_NET_SENDTOSELF + if (ip_route_output(&rt, daddr, rt->rt_spec_dst, RT_TOS(skb->nh.iph->tos), sk->bound_dev_if)) +#else if (ip_route_output(&rt, daddr, rt->rt_spec_dst, RT_TOS(skb->nh.iph->tos), 0)) +#endif return; /* And let IP do all the hard work. --- linux-2.4.19/net/ipv4/tcp_ipv4.c Fri Aug 2 17:39:46 2002 +++ linux-2.4.19.dev/net/ipv4/tcp_ipv4.c Sun Sep 15 21:25:42 2002 @@ -865,21 +865,36 @@ return h&(TCP_SYNQ_HSIZE-1); } +/** Netdevice ID can be wild-carded by making it zero. + */ static struct open_request *tcp_v4_search_req(struct tcp_opt *tp, struct open_request ***prevp, __u16 rport, - __u32 raddr, __u32 laddr) + __u32 raddr, __u32 laddr, + int netdevice_id) { struct tcp_listen_opt *lopt = tp->listen_opt; struct open_request *req, **prev; + /* Will only take netdevice_id into the equation if neither are + * 0. This should be backwards compatible with older code, and also + * let us connect to ourselves over external ports. Otherwise, we + * get confused about which connection is the originator v/s the + * receiver of the open request. --Ben + */ for (prev = &lopt->syn_table[tcp_v4_synq_hash(raddr, rport)]; (req = *prev) != NULL; prev = &req->dl_next) { if (req->rmt_port == rport && req->af.v4_req.rmt_addr == raddr && req->af.v4_req.loc_addr == laddr && - TCP_INET_FAMILY(req->class->family)) { + TCP_INET_FAMILY(req->class->family) +#ifdef CONFIG_NET_SENDTOSELF + && ((!netdevice_id) || (!req->bound_dev_if) || + (req->bound_dev_if == netdevice_id))) { +#else + ) { +#endif BUG_TRAP(req->sk == NULL); *prevp = prev; return req; @@ -899,7 +914,10 @@ req->retrans = 0; req->sk = NULL; req->dl_next = lopt->syn_table[h]; - +#ifdef CONFIG_NET_SENDTOSELF + req->bound_dev_if = sk->bound_dev_if; +#endif + write_lock(&tp->syn_wait_lock); lopt->syn_table[h] = req; write_unlock(&tp->syn_wait_lock); @@ -979,7 +997,8 @@ struct sock *sk; __u32 seq; int err; - + int netdevice_id = 0; + if (skb->len < (iph->ihl << 2) + 8) { ICMP_INC_STATS_BH(IcmpInErrors); return; @@ -1048,9 +1067,13 @@ if (sk->lock.users != 0) goto out; + if (skb->dev) { + netdevice_id = skb->dev->ifindex; + } + req = tcp_v4_search_req(tp, &prev, th->dest, - iph->daddr, iph->saddr); + iph->daddr, iph->saddr, netdevice_id); if (!req) goto out; @@ -1394,7 +1417,7 @@ #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */ #endif - /* Never answer to SYNs send to broadcast or multicast */ + /* Never answer to SYNs sent to broadcast or multicast */ if (((struct rtable *)skb->dst)->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST)) goto drop; @@ -1452,6 +1475,10 @@ req->af.v4_req.rmt_addr = saddr; req->af.v4_req.opt = tcp_v4_save_options(sk, skb); req->class = &or_ipv4; +#ifdef CONFIG_NET_SENDTOSELF + req->bound_dev_if = sk->bound_dev_if; +#endif + if (!want_cookie) TCP_ECN_create_request(req, skb->h.th); @@ -1587,11 +1614,12 @@ struct iphdr *iph = skb->nh.iph; struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp); struct sock *nsk; - + int device_id = tcp_v4_iif(skb); + /* Find possible connection requests. */ req = tcp_v4_search_req(tp, &prev, th->source, - iph->saddr, iph->daddr); + iph->saddr, iph->daddr, device_id); if (req) return tcp_check_req(sk, skb, req, prev); @@ -1599,7 +1627,7 @@ th->source, skb->nh.iph->daddr, ntohs(th->dest), - tcp_v4_iif(skb)); + device_id); if (nsk) { if (nsk->state != TCP_TIME_WAIT) {
--------------010703030901020509080500--
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