|
| From: | Li Zhijian |
| Subject: | Re: [Qemu-devel] [PATCH V3 2/3] net/filter-mirror:Add filter-redirector func |
| Date: | Mon, 7 Mar 2016 17:57:56 +0800 |
| User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 |
On 03/07/2016 05:09 PM, Jason Wang wrote:
On 03/07/2016 04:26 PM, Li Zhijian wrote:On 03/07/2016 03:56 PM, Jason Wang wrote:On 03/04/2016 08:01 PM, Zhang Chen wrote:Filter-redirector is a netfilter plugin. It gives qemu the ability to redirect net packet. redirector can redirect filter's net packet to outdev. and redirect indev's packet to filter. filter + | | redirector | +--------------+ | | | | | | | | | indev +-----------+ +----------> outdev | | | | | | | | | +--------------+ | | v filter usage: -netdev user,id=hn0 -chardev socket,id=s0,host=ip_primary,port=X,server,nowait -chardev socket,id=s1,host=ip_primary,port=Y,server,nowait -filter-redirector,id=r0,netdev=hn0,queue=tx/rx/all,indev=s0,outdev=s1 Signed-off-by: Zhang Chen <address@hidden> Signed-off-by: Wen Congyang <address@hidden> --- net/filter-mirror.c | 211 ++++++++++++++++++++++++++++++++++++++++++++++++++++ qemu-options.hx | 8 ++ vl.c | 3 +- 3 files changed, 221 insertions(+), 1 deletion(-) diff --git a/net/filter-mirror.c b/net/filter-mirror.c index 4ff7619..d137168 100644 --- a/net/filter-mirror.c +++ b/net/filter-mirror.c @@ -25,11 +25,19 @@ #define FILTER_MIRROR(obj) \ OBJECT_CHECK(MirrorState, (obj), TYPE_FILTER_MIRROR) +#define FILTER_REDIRECTOR(obj) \ + OBJECT_CHECK(MirrorState, (obj), TYPE_FILTER_REDIRECTOR) + #define TYPE_FILTER_MIRROR "filter-mirror" +#define TYPE_FILTER_REDIRECTOR "filter-redirector" +#define REDIRECT_HEADER_LEN sizeof(uint32_t) typedef struct MirrorState { NetFilterState parent_obj; + NetQueue *incoming_queue; + char *indev; char *outdev; + CharDriverState *chr_in; CharDriverState *chr_out; } MirrorState; @@ -67,6 +75,68 @@ err: return ret < 0 ? ret : -EIO; } +static int redirector_chr_can_read(void *opaque) +{ + return REDIRECT_HEADER_LEN; +} + +static void redirector_chr_read(void *opaque, const uint8_t *buf, int size) +{ + NetFilterState *nf = opaque; + MirrorState *s = FILTER_REDIRECTOR(nf); + uint32_t len; + int ret = 0; + uint8_t *recv_buf; + + memcpy(&len, buf, size);stack overflow if size > sizeof(len)?IIUC, it seems never happend because the 'size' will never greater than the return value of redirector_chr_can_read() which will always return REDIRECT_HEADER_LEN ?Right, so it's safe.+ if (size < REDIRECT_HEADER_LEN) { + ret = qemu_chr_fe_read_all(s->chr_in, ((uint8_t *)&len) + size, + REDIRECT_HEADER_LEN - size);There maybe some misunderstanding for my previous reply. You can have a look at net_socket_send() for reference. You could - use a buffer for storing len - each time when you receive partial len, store them in the buffer and advance the pointer until you receive at least sizeof(len) bytes.qemu_chr_fe_read_all() seem have done this work.Not the same. qemu_chr_fe_read_all() will do loop reading and usleep which is suboptimal. My proposal does not have this issue. It will make redirector_chr_read() can handle arbitrary length of data and won't do any busy reading.Do you mean that we implement a similar code to do that instead of qemu_chr_fe_read_all()Nope, if you have a look at net_socket_send() it won't do any usleep and loop reading, it will return immediately when it does not get sufficient data. But it's really your call, not a must but worth to be optimized on top in the future.
Thanks for you explain.
Is it just like bellow code(not completed) ?
#define REDIRECTOR_MAX_LEN NET_BUFSIZE
typedef struct MirrorState {
NetFilterState parent_obj;
char *indev;
char *outdev;
CharDriverState *chr_in;
CharDriverState *chr_out;
+ int state; /* 0 = getting length, 1 = getting data */
+ unsigned int index;
+ unsigned int packet_len;
+ uint8_t buf[REDIRECTOR_MAX_LEN];
} MirrorState;
static int redirector_chr_can_read(void *opaque)
{
return REDIRECTOR_MAX_LEN;
}
static void redirector_chr_read(void *opaque, const uint8_t *buf, int size)
{
NetFilterState *nf = opaque;
MirrorState *s = FILTER_REDIRECTOR(nf);
unsigned int l;
while (size > 0) {
/* reassemble a packet from the network */
switch (s->state) {
case 0:
l = 4 - s->index;
if (l > size) {
l = size;
}
memcpy(s->buf + s->index, buf, l);
buf += l;
size -= l;
s->index += l;
if (s->index == 4) {
/* got length */
s->packet_len = ntohl(*(uint32_t *)s->buf);
s->index = 0;
s->state = 1;
}
break;
case 1:
l = s->packet_len - s->index;
if (l > size) {
l = size;
}
if (s->index + l <= sizeof(s->buf)) {
memcpy(s->buf + s->index, buf, l);
} else {
fprintf(stderr, "serious error: oversized packet received,"
"connection terminated.\n");
s->state = 0;
/* TODO: do something
*/
}
s->index += l;
buf += l;
size -= l;
if (s->index >= s->packet_len) {
s->index = 0;
s->state = 0;
/*
* TODO: pass packet to next filter
*/
}
break;
}
}
}
Thanks
Li Zhijian
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