Re: [PATCH 3/3] net/colo-compare: Add handler for passthrough connection

From: Lukas Straub <lukasstraub2@web.de>
To: Zhang Chen <chen.zhang@intel.com >
Cc: Jason Wang <jasowang@redhat.com>,
	Markus Armbruster <armbru@redhat.com>,
	qemu-dev <qemu-devel@nongnu.org>,
	Zhang Chen <zhangckid@gmail.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [PATCH 3/3] net/colo-compare: Add handler for passthrough connection
Date: Thu, 14 Jan 2021 14:50:37 +0100	[thread overview]
Message-ID: <20210114145037.706fe8c7@gecko.fritz.box> (raw)
In-Reply-To: <20201224010918.19275-4-chen.zhang@intel.com>

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On Thu, 24 Dec 2020 09:09:18 +0800
Zhang Chen <chen.zhang@intel.com > wrote:

> From: Zhang Chen <chen.zhang@intel.com>
> 
> Currently, we just use guest's TCP/UDP source port as the key
> to bypass certain network traffic.
> 
> Signed-off-by: Zhang Chen <chen.zhang@intel.com>
> ---
>  net/colo-compare.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++
>  net/colo-compare.h |  2 ++
>  net/net.c          | 27 +++++++++++++++++++++++++
>  3 files changed, 78 insertions(+)
> 
> diff --git a/net/colo-compare.c b/net/colo-compare.c
> index 337025b44f..11a32caa9b 100644
> --- a/net/colo-compare.c
> +++ b/net/colo-compare.c
> @@ -46,6 +46,9 @@ static QTAILQ_HEAD(, CompareState) net_compares =
>  static NotifierList colo_compare_notifiers =
>      NOTIFIER_LIST_INITIALIZER(colo_compare_notifiers);
>  
> +static QLIST_HEAD(, PassthroughEntry) passthroughlist =
> +    QLIST_HEAD_INITIALIZER(passthroughlist);
> +
>  #define COMPARE_READ_LEN_MAX NET_BUFSIZE
>  #define MAX_QUEUE_SIZE 1024
>  
> @@ -103,6 +106,12 @@ typedef struct SendEntry {
>      uint8_t *buf;
>  } SendEntry;
>  
> +typedef struct PassthroughEntry {
> +    bool is_tcp;
> +    uint16_t port;
> +    QLIST_ENTRY(PassthroughEntry) node;
> +} PassthroughEntry;
> +
>  struct CompareState {
>      Object parent;
>  
> @@ -247,6 +256,7 @@ static int packet_enqueue(CompareState *s, int mode, Connection **con)
>      ConnectionKey key;
>      Packet *pkt = NULL;
>      Connection *conn;
> +    PassthroughEntry *bypass, *next;
>      int ret;
>  
>      if (mode == PRIMARY_IN) {
> @@ -264,8 +274,23 @@ static int packet_enqueue(CompareState *s, int mode, Connection **con)
>          pkt = NULL;
>          return -1;
>      }
> +
>      fill_connection_key(pkt, &key);
>  
> +    /* Check COLO passthrough connenction */
> +    if (!QLIST_EMPTY(&passthroughlist)) {
> +        QLIST_FOREACH_SAFE(bypass, &passthroughlist, node, next) {
> +            if (((key.ip_proto == IPPROTO_TCP) && bypass->is_tcp) ||
> +                ((key.ip_proto == IPPROTO_UDP) && !bypass->is_tcp)) {
> +                if (bypass->port == key.src_port) {
> +                    packet_destroy(pkt, NULL);
> +                    pkt = NULL;
> +                    return -1;
> +                }
> +            }
> +        }
> +    }
> +
>      conn = connection_get(s->connection_track_table,
>                            &key,
>                            &s->conn_list);
> @@ -1373,6 +1398,30 @@ static void colo_flush_packets(void *opaque, void *user_data)
>      }
>  }
>  
> +void colo_compare_passthrough_add(bool is_tcp, const uint16_t port)
> +{
> +    PassthroughEntry *bypass = NULL;
> +
> +    bypass = g_new0(PassthroughEntry, 1);
> +    bypass->is_tcp = is_tcp;
> +    bypass->port = port;
> +    QLIST_INSERT_HEAD(&passthroughlist, bypass, node);
> +}
> +
> +void colo_compare_passthrough_del(bool is_tcp, const uint16_t port)
> +{
> +    PassthroughEntry *bypass = NULL, *next = NULL;
> +
> +    if (!QLIST_EMPTY(&passthroughlist)) {
> +        QLIST_FOREACH_SAFE(bypass, &passthroughlist, node, next) {
> +            if ((bypass->is_tcp == is_tcp) && (bypass->port == port)) {
> +                QLIST_REMOVE(bypass, node);
> +                g_free(bypass);
> +            }
> +        }
> +    }
> +}
> +

Access to "passtroughlist" needs to be protected by a lock, as "packet_enqueue" is called from a different iothread.

>  static void colo_compare_class_init(ObjectClass *oc, void *data)
>  {
>      UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
> diff --git a/net/colo-compare.h b/net/colo-compare.h
> index 22ddd512e2..1fa026c85e 100644
> --- a/net/colo-compare.h
> +++ b/net/colo-compare.h
> @@ -20,5 +20,7 @@
>  void colo_notify_compares_event(void *opaque, int event, Error **errp);
>  void colo_compare_register_notifier(Notifier *notify);
>  void colo_compare_unregister_notifier(Notifier *notify);
> +void colo_compare_passthrough_add(bool is_tcp, const uint16_t port);
> +void colo_compare_passthrough_del(bool is_tcp, const uint16_t port);
>  
>  #endif /* QEMU_COLO_COMPARE_H */
> diff --git a/net/net.c b/net/net.c
> index eac7a92618..1f303e8309 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -55,6 +55,7 @@
>  #include "sysemu/sysemu.h"
>  #include "net/filter.h"
>  #include "qapi/string-output-visitor.h"
> +#include "net/colo-compare.h"
>  
>  /* Net bridge is currently not supported for W32. */
>  #if !defined(_WIN32)
> @@ -1155,12 +1156,38 @@ void qmp_colo_passthrough_add(const char *prot, const uint32_t port,
>                                Error **errp)
>  {
>      /* Setup passthrough connection */
> +    if (port > 65536) {
> +        error_setg(errp, "COLO pass through get wrong port");
> +        return;
> +    }
> +
> +    if (!strcmp(prot, "tcp") || !strcmp(prot, "TCP")) {
> +        colo_compare_passthrough_add(true, (uint16_t)port);
> +    } else if (!strcmp(prot, "udp") || !strcmp(prot, "UDP")) {
> +        colo_compare_passthrough_add(false, (uint16_t)port);
> +    } else {
> +        error_setg(errp, "COLO pass through just support tcp or udp protocol");
> +        return;
> +    }
>  }
>  
>  void qmp_colo_passthrough_del(const char *prot, const uint32_t port,
>                                Error **errp)
>  {
>      /* Delete passthrough connection */
> +    if (port > 65536) {
> +        error_setg(errp, "COLO pass through get wrong port");
> +        return;
> +    }
> +
> +    if (!strcmp(prot, "tcp") || !strcmp(prot, "TCP")) {
> +        colo_compare_passthrough_del(true, (uint16_t)port);
> +    } else if (!strcmp(prot, "udp") || !strcmp(prot, "UDP")) {
> +        colo_compare_passthrough_del(false, (uint16_t)port);
> +    } else {
> +        error_setg(errp, "COLO pass through just support tcp or udp protocol");
> +        return;
> +    }
>  }
>  
>  static void netfilter_print_info(Monitor *mon, NetFilterState *nf)

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