File 0021-core-serialize-deserialize-IP-accounting-a... of Package systemd

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File 0021-core-serialize-deserialize-IP-accounting-across-daem.patch of Package systemd (Revision 2a0ef622b860d89b09df9bc0f43c3432)

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From 790e74f970d58791cf9f8312920ffbd230511b21 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 7 Sep 2017 14:07:13 +0200
Subject: [PATCH 21/51] core: serialize/deserialize IP accounting across daemon
 reload/reexec

Make sure the current IP accounting counters aren't lost during
reload/reexec.

Note that we destroy all BPF file objects during a reload: the BPF
programs, the access and the accounting maps. The former two need to be
regenerated anyway with the newly loaded configuration data, but the
latter one needs to survive reloads/reexec. In this implementation I
opted to only save/restore the accounting map content instead of the map
itself. While this opens a (theoretic) window where IP traffic is still
accounted to the old map after we read it out, and we thus miss a few
bytes this has the benefit that we can alter the map layout between
versions should the need arise.

(cherry picked from commit 6b659ed87e98a69ab60ce2220f50a64af54a21d3)

[fbui: adjust context]
---
 src/core/cgroup.c | 15 +++++++++++++--
 src/core/unit.c   | 32 ++++++++++++++++++++++++++++++++
 src/core/unit.h   |  3 +++
 3 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 95eb342253..582cff69d1 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -2232,6 +2232,7 @@ int unit_get_ip_accounting(
                 CGroupIPAccountingMetric metric,
                 uint64_t *ret) {
 
+        uint64_t value;
         int fd, r;
 
         assert(u);
@@ -2247,9 +2248,17 @@ int unit_get_ip_accounting(
                 return -ENODATA;
 
         if (IN_SET(metric, CGROUP_IP_INGRESS_BYTES, CGROUP_IP_EGRESS_BYTES))
-                r = bpf_firewall_read_accounting(fd, ret, NULL);
+                r = bpf_firewall_read_accounting(fd, &value, NULL);
         else
-                r = bpf_firewall_read_accounting(fd, NULL, ret);
+                r = bpf_firewall_read_accounting(fd, NULL, &value);
+        if (r < 0)
+                return r;
+
+        /* Add in additional metrics from a previous runtime. Note that when reexecing/reloading the daemon we compile
+         * all BPF programs and maps anew, but serialize the old counters. When deserializing we store them in the
+         * ip_accounting_extra[] field, and add them in here transparently. */
+
+        *ret = value + u->ip_accounting_extra[metric];
 
         return r;
 }
@@ -2283,6 +2292,8 @@ int unit_reset_ip_accounting(Unit *u) {
         if (u->ip_accounting_egress_map_fd >= 0)
                 q = bpf_firewall_reset_accounting(u->ip_accounting_egress_map_fd);
 
+        zero(u->ip_accounting_extra);
+
         return r < 0 ? r : q;
 }
 
diff --git a/src/core/unit.c b/src/core/unit.c
index cacf35d0ea..1407e9fdb5 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2741,7 +2741,15 @@ static int unit_serialize_cgroup_mask(FILE *f, const char *key, CGroupMask mask)
         return r;
 }
 
+static const char *ip_accounting_metric_field[_CGROUP_IP_ACCOUNTING_METRIC_MAX] = {
+        [CGROUP_IP_INGRESS_BYTES] = "ip-accounting-ingress-bytes",
+        [CGROUP_IP_INGRESS_PACKETS] = "ip-accounting-ingress-packets",
+        [CGROUP_IP_EGRESS_BYTES] = "ip-accounting-egress-bytes",
+        [CGROUP_IP_EGRESS_PACKETS] = "ip-accounting-egress-packets",
+};
+
 int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
+        CGroupIPAccountingMetric m;
         int r;
 
         assert(u);
@@ -2802,6 +2810,14 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
 
         bus_track_serialize(u->bus_track, f, "ref");
 
+        for (m = 0; m < _CGROUP_IP_ACCOUNTING_METRIC_MAX; m++) {
+                uint64_t v;
+
+                r = unit_get_ip_accounting(u, m, &v);
+                if (r >= 0)
+                        unit_serialize_item_format(u, f, ip_accounting_metric_field[m], "%" PRIu64, v);
+        }
+
         if (serialize_jobs) {
                 if (u->job) {
                         fprintf(f, "job\n");
@@ -2908,6 +2924,7 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
 
         for (;;) {
                 _cleanup_free_ char *line = NULL;
+                CGroupIPAccountingMetric m;
                 char *l, *v;
                 size_t k;
 
@@ -3118,6 +3135,21 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
                         continue;
                 }
 
+                /* Check if this is an IP accounting metric serialization field */
+                for (m = 0; m < _CGROUP_IP_ACCOUNTING_METRIC_MAX; m++)
+                        if (streq(l, ip_accounting_metric_field[m]))
+                                break;
+                if (m < _CGROUP_IP_ACCOUNTING_METRIC_MAX) {
+                        uint64_t c;
+
+                        r = safe_atou64(v, &c);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse IP accounting value %s, ignoring.", v);
+                        else
+                                u->ip_accounting_extra[m] = c;
+                        continue;
+                }
+
                 if (unit_can_serialize(u)) {
                         if (rt) {
                                 r = exec_runtime_deserialize_item(u, rt, l, v, fds);
diff --git a/src/core/unit.h b/src/core/unit.h
index 9d2b9f4cac..ff7f60529f 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -34,6 +34,7 @@ typedef struct UnitStatusMessageFormats UnitStatusMessageFormats;
 #include "install.h"
 #include "list.h"
 #include "unit-name.h"
+#include "cgroup.h"
 
 typedef enum KillOperation {
         KILL_TERMINATE,
@@ -225,6 +226,8 @@ struct Unit {
         BPFProgram *ip_bpf_ingress;
         BPFProgram *ip_bpf_egress;
 
+        uint64_t ip_accounting_extra[_CGROUP_IP_ACCOUNTING_METRIC_MAX];
+
         /* How to start OnFailure units */
         JobMode on_failure_job_mode;
 
-- 
2.16.4

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File 0021-core-serialize-deserialize-IP-accounting-across-daem.patch of Package systemd (Revision 2a0ef622b860d89b09df9bc0f43c3432)

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