第9章 流量控制与QoS

struct Qdisc {
    struct Qdisc_ops *ops;
    struct net_device *dev;
    struct sk_buff_head q;
    struct gnet_stats_basic_packed bstats;
    struct gnet_stats_queue qstats;
    unsigned long state;
    struct sk_buff *gso_skb;
    u32 handle;
    u32 parent;
    int (*enqueue)(struct sk_buff *skb, struct Qdisc *sch);
    struct sk_buff *(*dequeue)(struct Qdisc *sch);
    // ... 更多字段
};

struct htb_class {
    struct Qdisc_class_common common;
    struct psched_ratecfg rate;
    struct psched_ratecfg ceil;
    s64 buffer, cbuffer;
    s64 mbuffer;
    struct htb_class *parent;
    struct htb_class *inner;
    struct htb_class *leaf;
    struct Qdisc *q;
    struct tcf_proto *filter_list;
    struct htb_class *next;
    // ... 更多字段
};

// simple_tc.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main() {
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("socket");
        return 1;
    }
    
    struct sockaddr_in addr = {
        .sin_family = AF_INET,
        .sin_port = htons(8080),
        .sin_addr.s_addr = INADDR_ANY
    };
    
    if (bind(sock, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
        perror("bind");
        close(sock);
        return 1;
    }
    
    if (listen(sock, 128) < 0) {
        perror("listen");
        close(sock);
        return 1;
    }
    
    printf("Server listening on port 8080\n");
    
    while (1) {
        struct sockaddr_in client_addr;
        socklen_t client_len = sizeof(client_addr);
        
        int client_sock = accept(sock, (struct sockaddr*)&client_addr, &client_len);
        if (client_sock < 0) {
            perror("accept");
            continue;
        }
        
        // 简单限速：每次发送1KB，间隔1ms
        char buffer[1024];
        memset(buffer, 'A', sizeof(buffer));
        
        for (int i = 0; i < 1000; i++) {
            if (send(client_sock, buffer, sizeof(buffer), 0) < 0) {
                perror("send");
                break;
            }
            usleep(1000); // 1ms延迟
        }
        
        close(client_sock);
    }
    
    close(sock);
    return 0;
}