【在线急等】Linux网络内核相关的问题？

品茶识书香 2011-12-06 02:50:47

我一直在做Android L2TP/IPsec 这块的代码，之前跟综上层没发现啥问题，后来我跟了下内核部分，
内核是：Linux2.6.35.3 的。

每次都是到L2TP发送SCCRQ的部分就发不出去，然后我就跟内核，总是在查找安全路由的时候被分到一个黑洞路由，然后我就看了看代码，代码大概是下面这个样子的，每次net->xfrm.sysctl_larval_drop总是通过，然后就制做了一个黑洞路由。



	if (route == NULL && num_xfrms > 0) {

		/* The only case when xfrm_bundle_lookup() returns a

		 * bundle with null route, is when the template could

		 * not be resolved. It means policies are there, but

		 * bundle could not be created, since we don't yet

		 * have the xfrm_state's. We need to wait for KM to

		 * negotiate new SA's or bail out with error.*/

		if (net->xfrm.sysctl_larval_drop) {

			/* EREMOTE tells the caller to generate

			 * a one-shot blackhole route. */

			dst_release(dst);

			xfrm_pols_put(pols, drop_pols);

			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);



			return make_blackhole(net, family, dst_orig);

		}

         .....

         }

后来我又看了下初始化net->xfrm.sysctl_larval_drop的地方，是在xfrm_sysctl.c中的__xfrm_sysctl_init函数。代码是下面这个样子



static void __net_init __xfrm_sysctl_init(struct net *net)

{

	net->xfrm.sysctl_aevent_etime = XFRM_AE_ETIME;

	net->xfrm.sysctl_aevent_rseqth = XFRM_AE_SEQT_SIZE;

	net->xfrm.sysctl_larval_drop = 1;//改的这里

	net->xfrm.sysctl_acq_expires = 30;

}

后来我就把这个net->xfrm.sysctl_larval_drop这行改成了等于0



static void __net_init __xfrm_sysctl_init(struct net *net)

{

	net->xfrm.sysctl_aevent_etime = XFRM_AE_ETIME;

	net->xfrm.sysctl_aevent_rseqth = XFRM_AE_SEQT_SIZE;

	net->xfrm.sysctl_larval_drop = 0;//改的这里

	net->xfrm.sysctl_acq_expires = 30;

}

这时候重新编译了下内核，然后把生成的包烧进android的机子，这时ipsec确实正常通过了，可是在日志上却出现了下面这样的情况

12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.544692] ------------[ cut here ]------------
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.544739] WARNING: at /home/b617/git/bbdev/hardware/intel/linux-2.6/include/linux/skbuff.h:474 xfrm_output_resume+0x2fc/0x351()
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.544765] Modules linked in: tiwlan_drv atomisp lm3554 mt9m114 mt9e013 videobuf_vmalloc videobuf_dma_contig videobuf_core bt_drv st_drv sdio [last unloaded: tiwlan_drv]
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.544914] Pid: 3329, comm: mtpd Tainted: G W 2.6.35.3+ #11
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.544932] Call Trace:
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.544977] [<c123175b>] warn_slowpath_common+0x4a/0xa6
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.545012] [<c160359a>] ? xfrm_output_resume+0x2fc/0x351
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.545050] [<c12317c6>] warn_slowpath_null+0xf/0x13
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.545086] [<c160359a>] xfrm_output_resume+0x2fc/0x351
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.545125] [<c160369d>] xfrm_output+0x9f/0xaa
12-06 13:21:46.606 W/Kernel-Dmesg( 0): <4>[ 4563.545162] [<c15fc5d9>] xfrm4_output_finish+0x39/0x3c
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545195] [<c15fc631>] xfrm4_output+0x55/0x5c
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545230] [<c15be6f7>] dst_output+0x12/0x15
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545263] [<c15bfc3f>] ip_local_out+0x93/0x9a
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545298] [<c15bfeb7>] ip_push_pending_frames+0x271/0x2e4
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545338] [<c15da561>] udp_push_pending_frames+0x27f/0x2e0
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545374] [<c15db3bf>] ? udp_sendmsg+0x440/0x53a
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545411] [<c15db3de>] udp_sendmsg+0x45f/0x53a
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545453] [<c15e0608>] ? rcu_read_lock+0x0/0x2b
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545490] [<c15e0608>] ? rcu_read_lock+0x0/0x2b
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545530] [<c122709f>] ? get_parent_ip+0xb/0x31
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545567] [<c15e0cf5>] inet_sendmsg+0x47/0x50
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545606] [<c1576a44>] sock_sendmsg+0xc0/0xdb
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545648] [<c122435c>] ? __wake_up+0x32/0x3b
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545688] [<c14e82c3>] ? logger_aio_write+0x262/0x277
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545737] [<c1577432>] sys_sendto+0xc3/0xdf
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545785] [<c12a7b3c>] ? fsnotify_modify+0x5d/0x68
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545833] [<c1578548>] sys_socketcall+0x16d/0x3c1
12-06 13:21:46.610 W/Kernel-Dmesg( 0): <4>[ 4563.545874] [<c12a8473>] ? vfs_writev+0x36/0x44
12-06 13:21:46.615 W/Kernel-Dmesg( 0): <4>[ 4563.545916] [<c16b50dd>] syscall_call+0x7/0xb
12-06 13:21:46.615 W/Kernel-Dmesg( 0): <4>[ 4563.545947] ---[ end trace 01e818355159b7b9 ]---

我不明白上面的日志信息是什么意思，还有我改的那行代码是什么意思？望高手指点（net->xfrm.sysctl_larval_drop）

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