Re: [Qemu-devel] [PATCH V2] net/net: Add SocketReadState for reuse codes

[Jason Wang <jasowang@redhat.com>]

On 2016年05月12日 17:19, Zhang Chen wrote:
> This function is from net/socket.c, move it to net.c and net.h.
> Add SocketReadState to make others reuse net_fill_rstate().
> suggestion from jason.
>
> v2:
>   - rename ReadState to SocketReadState
>   - add SocketReadState init and finalize callback
>
> v1:
>   - init patch
>
> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>   include/net/net.h   | 14 +++++++++
>   net/filter-mirror.c | 72 ++++++++++++++-----------------------------
>   net/net.c           | 65 ++++++++++++++++++++++++++++++++++++++
>   net/socket.c        | 89 +++++++++++++++++++++--------------------------------
>   4 files changed, 137 insertions(+), 103 deletions(-)
>
> diff --git a/include/net/net.h b/include/net/net.h
> index 73e4c46..4f6b6bf 100644
> --- a/include/net/net.h
> +++ b/include/net/net.h
> @@ -57,6 +57,9 @@ typedef void (SetOffload)(NetClientState *, int, int, int, int, int);
>   typedef void (SetVnetHdrLen)(NetClientState *, int);
>   typedef int (SetVnetLE)(NetClientState *, bool);
>   typedef int (SetVnetBE)(NetClientState *, bool);
> +typedef struct SocketReadState SocketReadState;
> +typedef void (SocketReadStateInit)(SocketReadState *rs);
> +typedef void (SocketReadStateFinalize)(SocketReadState *rs);
>   
>   typedef struct NetClientInfo {
>       NetClientOptionsKind type;
> @@ -102,6 +105,16 @@ typedef struct NICState {
>       bool peer_deleted;
>   } NICState;
>   
> +struct SocketReadState {
> +    int state; /* 0 = getting length, 1 = getting data */
> +    uint32_t index;
> +    uint32_t packet_len;
> +    uint8_t buf[NET_BUFSIZE];
> +    SocketReadStateInit *init;
> +    SocketReadStateFinalize *finalize;
> +};
> +
> +int net_fill_rstate(SocketReadState *rs, const uint8_t *buf, int size);
>   char *qemu_mac_strdup_printf(const uint8_t *macaddr);
>   NetClientState *qemu_find_netdev(const char *id);
>   int qemu_find_net_clients_except(const char *id, NetClientState **ncs,
> @@ -160,6 +173,7 @@ ssize_t qemu_deliver_packet_iov(NetClientState *sender,
>   
>   void print_net_client(Monitor *mon, NetClientState *nc);
>   void hmp_info_network(Monitor *mon, const QDict *qdict);
> +void net_socket_rs_init(SocketReadState *rs);
>   
>   /* NIC info */
>   
> diff --git a/net/filter-mirror.c b/net/filter-mirror.c
> index c0c4dc6..4e55924 100644
> --- a/net/filter-mirror.c
> +++ b/net/filter-mirror.c
> @@ -40,10 +40,7 @@ typedef struct MirrorState {
>       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];
> +    SocketReadState rs;
>   } MirrorState;
>   
>   static int filter_mirror_send(CharDriverState *chr_out,
> @@ -108,50 +105,15 @@ 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) { /* 0 = getting length, 1 = getting data */
> -        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 {
> -                error_report("serious error: oversized packet received.");
> -                s->index = s->state = 0;
> -                qemu_chr_add_handlers(s->chr_in, NULL, NULL, NULL, NULL);
> -                return;
> -            }
> -
> -            s->index += l;
> -            buf += l;
> -            size -= l;
> -            if (s->index >= s->packet_len) {
> -                s->index = 0;
> -                s->state = 0;
> -                redirector_to_filter(nf, s->buf, s->packet_len);
> -            }
> -            break;
> +    int ret;
> +
> +    ret = net_fill_rstate(&s->rs, buf, size);
> +
> +    if (ret == -1) {
> +        qemu_chr_add_handlers(s->chr_in, NULL, NULL, NULL, NULL);
> +    } else if (ret == 1) {
> +        if (s->rs.finalize) {
> +            s->rs.finalize(&s->rs);

Why not simply call this in net_fill_rstate()?

>           }
>       }
>   }
> @@ -258,6 +220,14 @@ static void filter_mirror_setup(NetFilterState *nf, Error **errp)
>       }
>   }
>   
> +static void redirector_rs_finalize(SocketReadState *rs)
> +{
> +    MirrorState *s = container_of(rs, MirrorState, rs);
> +    NetFilterState *nf = NETFILTER(s);
> +
> +    redirector_to_filter(nf, rs->buf, rs->packet_len);
> +}
> +
>   static void filter_redirector_setup(NetFilterState *nf, Error **errp)
>   {
>       MirrorState *s = FILTER_REDIRECTOR(nf);
> @@ -274,7 +244,11 @@ static void filter_redirector_setup(NetFilterState *nf, Error **errp)
>           }
>       }
>   
> -    s->state = s->index = 0;
> +    s->rs.init = net_socket_rs_init;
> +    s->rs.finalize = redirector_rs_finalize;
> +    if (s->rs.init) {
> +        s->rs.init(&s->rs);
> +    }

This looks odd, you can call net_socket_rs_init() directly here and pass 
redirector_rs_finalize to it. Then there's no need to do the open code here.