cregit-Linux how code gets into the kernel

Release 4.16 samples/bpf/xdp_rxq_info_user.c

Directory: samples/bpf
/* SPDX-License-Identifier: GPL-2.0
 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
 */

static const char *__doc__ = " XDP RX-queue info extract example\n\n"
	"Monitor how many packets per sec (pps) are received\n"
	"per NIC RX queue index and which CPU processed the packet\n"
	;

#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <locale.h>
#include <sys/resource.h>
#include <getopt.h>
#include <net/if.h>
#include <time.h>

#include <arpa/inet.h>
#include <linux/if_link.h>

#include "libbpf.h"
#include "bpf_load.h"
#include "bpf_util.h"


static int ifindex = -1;

static char ifname_buf[IF_NAMESIZE];

static char *ifname;


static __u32 xdp_flags;

/* Exit return codes */

#define EXIT_OK		0

#define EXIT_FAIL		1

#define EXIT_FAIL_OPTION	2

#define EXIT_FAIL_XDP		3

#define EXIT_FAIL_BPF		4

#define EXIT_FAIL_MEM		5


static const struct option long_options[] = {
	{"help",	no_argument,		NULL, 'h' },
	{"dev",		required_argument,	NULL, 'd' },
	{"skb-mode",	no_argument,		NULL, 'S' },
	{"sec",		required_argument,	NULL, 's' },
	{"no-separators", no_argument,		NULL, 'z' },
	{"action",	required_argument,	NULL, 'a' },
	{0, 0, NULL,  0 }
};


static void int_exit(int sig) { fprintf(stderr, "Interrupted: Removing XDP program on ifindex:%d device:%s\n", ifindex, ifname); if (ifindex > -1) bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); exit(EXIT_OK); }

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Jesper Dangaard Brouer4197.62%150.00%
Eric Leblond12.38%150.00%
Total42100.00%2100.00%

struct config { __u32 action; int ifindex; }; #define XDP_ACTION_MAX (XDP_TX + 1) #define XDP_ACTION_MAX_STRLEN 11 static const char *xdp_action_names[XDP_ACTION_MAX] = { [XDP_ABORTED] = "XDP_ABORTED", [XDP_DROP] = "XDP_DROP", [XDP_PASS] = "XDP_PASS", [XDP_TX] = "XDP_TX", };
static const char *action2str(int action) { if (action < XDP_ACTION_MAX) return xdp_action_names[action]; return NULL; }

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Jesper Dangaard Brouer26100.00%1100.00%
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static int parse_xdp_action(char *action_str) { size_t maxlen; __u64 action = -1; int i; for (i = 0; i < XDP_ACTION_MAX; i++) { maxlen = XDP_ACTION_MAX_STRLEN; if (strncmp(xdp_action_names[i], action_str, maxlen) == 0) { action = i; break; } } return action; }

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Jesper Dangaard Brouer67100.00%1100.00%
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static void list_xdp_actions(void) { int i; printf("Available XDP --action <options>\n"); for (i = 0; i < XDP_ACTION_MAX; i++) printf("\t%s\n", xdp_action_names[i]); printf("\n"); }

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static void usage(char *argv[]) { int i; printf("\nDOCUMENTATION:\n%s\n", __doc__); printf(" Usage: %s (options-see-below)\n", argv[0]); printf(" Listing options:\n"); for (i = 0; long_options[i].name != 0; i++) { printf(" --%-12s", long_options[i].name); if (long_options[i].flag != NULL) printf(" flag (internal value:%d)", *long_options[i].flag); else printf(" short-option: -%c", long_options[i].val); printf("\n"); } printf("\n"); list_xdp_actions(); }

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Jesper Dangaard Brouer118100.00%1100.00%
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#define NANOSEC_PER_SEC 1000000000 /* 10^9 */
static __u64 gettime(void) { struct timespec t; int res; res = clock_gettime(CLOCK_MONOTONIC, &t); if (res < 0) { fprintf(stderr, "Error with gettimeofday! (%i)\n", res); exit(EXIT_FAIL); } return (__u64) t.tv_sec * NANOSEC_PER_SEC + t.tv_nsec; }

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Jesper Dangaard Brouer61100.00%1100.00%
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/* Common stats data record shared with _kern.c */ struct datarec { __u64 processed; __u64 issue; }; struct record { __u64 timestamp; struct datarec total; struct datarec *cpu; }; struct stats_record { struct record stats; struct record *rxq; };
static struct datarec *alloc_record_per_cpu(void) { unsigned int nr_cpus = bpf_num_possible_cpus(); struct datarec *array; size_t size; size = sizeof(struct datarec) * nr_cpus; array = malloc(size); memset(array, 0, size); if (!array) { fprintf(stderr, "Mem alloc error (nr_cpus:%u)\n", nr_cpus); exit(EXIT_FAIL_MEM); } return array; }

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Jesper Dangaard Brouer75100.00%1100.00%
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static struct record *alloc_record_per_rxq(void) { unsigned int nr_rxqs = map_data[2].def.max_entries; struct record *array; size_t size; size = sizeof(struct record) * nr_rxqs; array = malloc(size); memset(array, 0, size); if (!array) { fprintf(stderr, "Mem alloc error (nr_rxqs:%u)\n", nr_rxqs); exit(EXIT_FAIL_MEM); } return array; }

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Jesper Dangaard Brouer81100.00%1100.00%
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static struct stats_record *alloc_stats_record(void) { unsigned int nr_rxqs = map_data[2].def.max_entries; struct stats_record *rec; int i; rec = malloc(sizeof(*rec)); memset(rec, 0, sizeof(*rec)); if (!rec) { fprintf(stderr, "Mem alloc error\n"); exit(EXIT_FAIL_MEM); } rec->rxq = alloc_record_per_rxq(); for (i = 0; i < nr_rxqs; i++) rec->rxq[i].cpu = alloc_record_per_cpu(); rec->stats.cpu = alloc_record_per_cpu(); return rec; }

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Jesper Dangaard Brouer118100.00%1100.00%
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static void free_stats_record(struct stats_record *r) { unsigned int nr_rxqs = map_data[2].def.max_entries; int i; for (i = 0; i < nr_rxqs; i++) free(r->rxq[i].cpu); free(r->rxq); free(r->stats.cpu); free(r); }

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Jesper Dangaard Brouer73100.00%1100.00%
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static bool map_collect_percpu(int fd, __u32 key, struct record *rec) { /* For percpu maps, userspace gets a value per possible CPU */ unsigned int nr_cpus = bpf_num_possible_cpus(); struct datarec values[nr_cpus]; __u64 sum_processed = 0; __u64 sum_issue = 0; int i; if ((bpf_map_lookup_elem(fd, &key, values)) != 0) { fprintf(stderr, "ERR: bpf_map_lookup_elem failed key:0x%X\n", key); return false; } /* Get time as close as possible to reading map contents */ rec->timestamp = gettime(); /* Record and sum values from each CPU */ for (i = 0; i < nr_cpus; i++) { rec->cpu[i].processed = values[i].processed; sum_processed += values[i].processed; rec->cpu[i].issue = values[i].issue; sum_issue += values[i].issue; } rec->total.processed = sum_processed; rec->total.issue = sum_issue; return true; }

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Jesper Dangaard Brouer168100.00%1100.00%
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static void stats_collect(struct stats_record *rec) { int fd, i, max_rxqs; fd = map_data[1].fd; /* map: stats_global_map */ map_collect_percpu(fd, 0, &rec->stats); fd = map_data[2].fd; /* map: rx_queue_index_map */ max_rxqs = map_data[2].def.max_entries; for (i = 0; i < max_rxqs; i++) map_collect_percpu(fd, i, &rec->rxq[i]); }

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Jesper Dangaard Brouer89100.00%1100.00%
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static double calc_period(struct record *r, struct record *p) { double period_ = 0; __u64 period = 0; period = r->timestamp - p->timestamp; if (period > 0) period_ = ((double) period / NANOSEC_PER_SEC); return period_; }

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Jesper Dangaard Brouer56100.00%1100.00%
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static __u64 calc_pps(struct datarec *r, struct datarec *p, double period_) { __u64 packets = 0; __u64 pps = 0; if (period_ > 0) { packets = r->processed - p->processed; pps = packets / period_; } return pps; }

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Jesper Dangaard Brouer56100.00%1100.00%
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static __u64 calc_errs_pps(struct datarec *r, struct datarec *p, double period_) { __u64 packets = 0; __u64 pps = 0; if (period_ > 0) { packets = r->issue - p->issue; pps = packets / period_; } return pps; }

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Jesper Dangaard Brouer56100.00%1100.00%
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static void stats_print(struct stats_record *stats_rec, struct stats_record *stats_prev, int action) { unsigned int nr_cpus = bpf_num_possible_cpus(); unsigned int nr_rxqs = map_data[2].def.max_entries; double pps = 0, err = 0; struct record *rec, *prev; double t; int rxq; int i; /* Header */ printf("\nRunning XDP on dev:%s (ifindex:%d) action:%s\n", ifname, ifindex, action2str(action)); /* stats_global_map */ { char *fmt_rx = "%-15s %-7d %'-11.0f %'-10.0f %s\n"; char *fm2_rx = "%-15s %-7s %'-11.0f\n"; char *errstr = ""; printf("%-15s %-7s %-11s %-11s\n", "XDP stats", "CPU", "pps", "issue-pps"); rec = &stats_rec->stats; prev = &stats_prev->stats; t = calc_period(rec, prev); for (i = 0; i < nr_cpus; i++) { struct datarec *r = &rec->cpu[i]; struct datarec *p = &prev->cpu[i]; pps = calc_pps (r, p, t); err = calc_errs_pps(r, p, t); if (err > 0) errstr = "invalid-ifindex"; if (pps > 0) printf(fmt_rx, "XDP-RX CPU", i, pps, err, errstr); } pps = calc_pps (&rec->total, &prev->total, t); err = calc_errs_pps(&rec->total, &prev->total, t); printf(fm2_rx, "XDP-RX CPU", "total", pps, err); } /* rx_queue_index_map */ printf("\n%-15s %-7s %-11s %-11s\n", "RXQ stats", "RXQ:CPU", "pps", "issue-pps"); for (rxq = 0; rxq < nr_rxqs; rxq++) { char *fmt_rx = "%-15s %3d:%-3d %'-11.0f %'-10.0f %s\n"; char *fm2_rx = "%-15s %3d:%-3s %'-11.0f\n"; char *errstr = ""; int rxq_ = rxq; /* Last RXQ in map catch overflows */ if (rxq_ == nr_rxqs - 1) rxq_ = -1; rec = &stats_rec->rxq[rxq]; prev = &stats_prev->rxq[rxq]; t = calc_period(rec, prev); for (i = 0; i < nr_cpus; i++) { struct datarec *r = &rec->cpu[i]; struct datarec *p = &prev->cpu[i]; pps = calc_pps (r, p, t); err = calc_errs_pps(r, p, t); if (err > 0) { if (rxq_ == -1) errstr = "map-overflow-RXQ"; else errstr = "err"; } if (pps > 0) printf(fmt_rx, "rx_queue_index", rxq_, i, pps, err, errstr); } pps = calc_pps (&rec->total, &prev->total, t); err = calc_errs_pps(&rec->total, &prev->total, t); if (pps || err) printf(fm2_rx, "rx_queue_index", rxq_, "sum", pps, err); } }

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/* Pointer swap trick */
static inline void swap(struct stats_record **a, struct stats_record **b) { struct stats_record *tmp; tmp = *a; *a = *b; *b = tmp; }

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Jesper Dangaard Brouer40100.00%1100.00%
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static void stats_poll(int interval, int action) { struct stats_record *record, *prev; record = alloc_stats_record(); prev = alloc_stats_record(); stats_collect(record); while (1) { swap(&prev, &record); stats_collect(record); stats_print(record, prev, action); sleep(interval); } free_stats_record(record); free_stats_record(prev); }

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Jesper Dangaard Brouer79100.00%1100.00%
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int main(int argc, char **argv) { struct rlimit r = {10 * 1024 * 1024, RLIM_INFINITY}; bool use_separators = true; struct config cfg = { 0 }; char filename[256]; int longindex = 0; int interval = 2; __u32 key = 0; int opt, err; char action_str_buf[XDP_ACTION_MAX_STRLEN + 1 /* for \0 */] = { 0 }; int action = XDP_PASS; /* Default action */ char *action_str = NULL; snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); if (setrlimit(RLIMIT_MEMLOCK, &r)) { perror("setrlimit(RLIMIT_MEMLOCK)"); return 1; } if (load_bpf_file(filename)) { fprintf(stderr, "ERR in load_bpf_file(): %s", bpf_log_buf); return EXIT_FAIL; } if (!prog_fd[0]) { fprintf(stderr, "ERR: load_bpf_file: %s\n", strerror(errno)); return EXIT_FAIL; } /* Parse commands line args */ while ((opt = getopt_long(argc, argv, "hSd:", long_options, &longindex)) != -1) { switch (opt) { case 'd': if (strlen(optarg) >= IF_NAMESIZE) { fprintf(stderr, "ERR: --dev name too long\n"); goto error; } ifname = (char *)&ifname_buf; strncpy(ifname, optarg, IF_NAMESIZE); ifindex = if_nametoindex(ifname); if (ifindex == 0) { fprintf(stderr, "ERR: --dev name unknown err(%d):%s\n", errno, strerror(errno)); goto error; } break; case 's': interval = atoi(optarg); break; case 'S': xdp_flags |= XDP_FLAGS_SKB_MODE; break; case 'z': use_separators = false; break; case 'a': action_str = (char *)&action_str_buf; strncpy(action_str, optarg, XDP_ACTION_MAX_STRLEN); break; case 'h': error: default: usage(argv); return EXIT_FAIL_OPTION; } } /* Required option */ if (ifindex == -1) { fprintf(stderr, "ERR: required option --dev missing\n"); usage(argv); return EXIT_FAIL_OPTION; } cfg.ifindex = ifindex; /* Parse action string */ if (action_str) { action = parse_xdp_action(action_str); if (action < 0) { fprintf(stderr, "ERR: Invalid XDP --action: %s\n", action_str); list_xdp_actions(); return EXIT_FAIL_OPTION; } } cfg.action = action; /* Trick to pretty printf with thousands separators use %' */ if (use_separators) setlocale(LC_NUMERIC, "en_US"); /* User-side setup ifindex in config_map */ err = bpf_map_update_elem(map_fd[0], &key, &cfg, 0); if (err) { fprintf(stderr, "Store config failed (err:%d)\n", err); exit(EXIT_FAIL_BPF); } /* Remove XDP program when program is interrupted */ signal(SIGINT, int_exit); if (bpf_set_link_xdp_fd(ifindex, prog_fd[0], xdp_flags) < 0) { fprintf(stderr, "link set xdp fd failed\n"); return EXIT_FAIL_XDP; } stats_poll(interval, action); return EXIT_OK; }

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Total515100.00%2100.00%


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Directory: samples/bpf
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